Spectroscopy of element 115 decay chains.

Science.gov (United States)

Rudolph, D; Forsberg, U; Golubev, P; Sarmiento, L G; Yakushev, A; Andersson, L-L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Gregorich, K E; Gross, C J; Heßberger, F P; Herzberg, R-D; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Schädel, M; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

2013-09-13

A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

A general algorithm for radioactive decay with branching and loss from a medium

International Nuclear Information System (INIS)

Strenge, D.L.

1995-07-01

Many areas in the field of health physics require evaluation of the change of radionuclide quantity in a medium with time. A general solution to first-order compartmental models is presented in this paper for application to systems consisting of one physical medium that contains any number of radionuclide decay chain members. The general analytical solution to the problem is first described mathematically, and then extended to four applications: (1) evaluation of the quantity of radionuclides as a function of time, (2) evaluation of the time integral of the quantity during a time period, (3) evaluation of the amount in a medium as a function of time following deposition at a constant rate, and (4) evaluation of the time integral of the amount in a medium after deposition at a constant rate for a time. The solution can be applied to any system involving physical transfers from the medium and radioactive chain decay with branching in the medium. The general solution is presented for quantities expressed in units of atoms and activity. Unlike many earlier mathematical solutions, this solution includes chain decay with branching explicitly in the equations

Radioactive-nuclide decay data in science and technology

International Nuclear Information System (INIS)

Reich, C.W.; Helmer, R.G.

1975-01-01

The scope of ENDF/B has recently been expanded to include radioactive-nuclide decay data. In this paper, the content and organization of the decay data which are included in ENDF/B are presented and discussed. The application of decay data in a wide variety of nuclear-related activities is illustrated by a number of examples. Two items pointed up by the ENDF/B decay-data compilation effort are treated: the identification of deficiencies in the data; and the importance of a radioactive-nuclide metrology effort oriented toward supplying these needs in a systematic fashion. 3 figures, 2 tables

Radioactive-nuclide decay data in science and technology

International Nuclear Information System (INIS)

Reich, C.W.; Helmer, R.G.

1975-01-01

The scope of ENDF/B has recently been expanded to include radioactive-nuclide decay data. In this paper, the content and organization of the decay data which are included in ENDF/B are presented and discussed. The application of decay data in a wide variety of nuclear-related activities is illustrated by a number of examples. Two items pointed up by the ENDF/B decay-data compilation effort are treated: the identification of deficiencies in the data; and the importance of a radioactive-nuclide metrology effort oriented toward supplying these needs in a systematic fashion. (3 figures, 1 table)

The law of radioactive decay

International Nuclear Information System (INIS)

Bouyrie, G

2004-01-01

This article deals with the law of radioactive decay (Rutherford-Sody's law) and the way to explain it to high-school or grammar-school students. The mathematical content of the law is recalled and its experimental validation is proposed through the study of the decay of a population of radon-220 atoms. The analysis of the experimental data is made easier by using software such as Generis, Regressi or even Excel

Physical distributions of radon decay chain activities in air

International Nuclear Information System (INIS)

Rolle, R.

2004-01-01

The distribution of short-lived radon decay chain activities in air - in time, space and on aerosols - determines their exposure potential and measurement thereof. The radioactive decay constants and flow variables in a flow system combine, yielding activity concentration distributions and ratios of concentrations characteristic of the flow scheme, its source(s) and sink(s). The clock of 'internal' decay constants allows the unraveling of characteristics of the flow scheme from activity concentration measurements of individual members of a decay chain. Basic flow string calculations are shown. These can be assembled to define or simulate concentrations in a single- or multiple-compartment flow network. Response calculations to single- and multiple-step, or continuous changes in sources and sinks yield time-, spatial- and attachment-distributions. For the short-lived 222 Rn and 212 Pb decay chains the decay constants of the shorter-lived progeny in relation to the parent impose air activity ratios on successive chain members. Ratio limits had been used in the past to improve older grab-sampling- or integral gross-alpha measurement procedures for assessing exposure level. Assessment of individual concentrations, ratios and their distributions enables unravelling of dynamic flow systems, with restriction from the range of the parameters of flow and decay. An activity measuring instrument by itself represents a flow system with a response time distribution. Instrument response correction during continuous or quasi-continuous sampling and continuous spectrometric measurement allows far more accurate time-resolved measurement evaluation of continuously varying air concentrations, than previously attainable. Strong diurnal or even shorter (≤ 1 hr) changes probably are the norm in indoor and outdoor air activity concentrations. A mere average response evaluation, as used in steady state instrument calibration, and using less efficient instruments, is usually inadequate

Application of the Laplace transform method for computational modelling of radioactive decay series

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Deise L.; Damasceno, Ralf M.; Barros, Ricardo C. [Univ. do Estado do Rio de Janeiro (IME/UERJ) (Brazil). Programa de Pos-graduacao em Ciencias Computacionais

2012-03-15

It is well known that when spent fuel is removed from the core, it is still composed of considerable amount of radioactive elements with significant half-lives. Most actinides, in particular plutonium, fall into this category, and have to be safely disposed of. One solution is to store the long-lived spent fuel as it is, by encasing and burying it deep underground in a stable geological formation. This implies estimating the transmutation of these radioactive elements with time. Therefore, we describe in this paper the application of the Laplace transform technique in matrix formulation to analytically solve initial value problems that mathematically model radioactive decay series. Given the initial amount of each type of radioactive isotopes in the decay series, the computer code generates the amount at a given time of interest, or may plot a graph of the evolution in time of the amount of each type of isotopes in the series. This computer code, that we refer to as the LTRad{sub L} code, where L is the number of types of isotopes belonging to the series, was developed using the Scilab free platform for numerical computation and can model one segment or the entire chain of any of the three radioactive series existing on Earth today. Numerical results are given to typical model problems to illustrate the computer code efficiency and accuracy. (orig.)

Application of the Laplace transform method for computational modelling of radioactive decay series

International Nuclear Information System (INIS)

Oliveira, Deise L.; Damasceno, Ralf M.; Barros, Ricardo C.

2012-01-01

It is well known that when spent fuel is removed from the core, it is still composed of considerable amount of radioactive elements with significant half-lives. Most actinides, in particular plutonium, fall into this category, and have to be safely disposed of. One solution is to store the long-lived spent fuel as it is, by encasing and burying it deep underground in a stable geological formation. This implies estimating the transmutation of these radioactive elements with time. Therefore, we describe in this paper the application of the Laplace transform technique in matrix formulation to analytically solve initial value problems that mathematically model radioactive decay series. Given the initial amount of each type of radioactive isotopes in the decay series, the computer code generates the amount at a given time of interest, or may plot a graph of the evolution in time of the amount of each type of isotopes in the series. This computer code, that we refer to as the LTRad L code, where L is the number of types of isotopes belonging to the series, was developed using the Scilab free platform for numerical computation and can model one segment or the entire chain of any of the three radioactive series existing on Earth today. Numerical results are given to typical model problems to illustrate the computer code efficiency and accuracy. (orig.)

Alpha-decay chains of superheavy nuclei 292-296118

Science.gov (United States)

Singh, U. K.; Kumawat, M.; Saxena, G.; Kaushik, M.; Jain, S. K.

2018-05-01

We have employed relativistic mean-field plus BCS (RMF+BCS) approach for the study of even-even superheavy nuclei with Z = 118 which is the last and recent observed element in the periodic chart so far. Our study includes binding energies, Qα values, alpha-decay half-lives and spontaneous decay half-lives along with comparison of available experimental data and the results of FRDM calculations. We find an excellent match with the only known decay chain of 294118 for Z = 118 so far and predict decay chain of 292118 and 296118 in consistency with known experimental decay chains and FRDM results. These results may provide a very helpful insight to conduct experiments for realizing the presence of nuclei with Z = 118.

Superheavy-element spectroscopy: Correlations along element 115 decay chains

Science.gov (United States)

Rudolph, D.; Forsberg, U.; Sarmiento, L. G.; Golubev, P.; Fahlander, C.

2016-05-01

Following a brief summary of the region of the heaviest atomic nuclei yet created in the laboratory, data on more than hundred α-decay chains associated with the production of element 115 are combined to investigate time and energy correlations along the observed decay chains. Several of these are analysed using a new method for statistical assessments of lifetimes in sets of decay chains.

Nuclide radioactive decay data uncertainties library

International Nuclear Information System (INIS)

Barabanova, D S; Zherdev, G M

2017-01-01

The results of the developing the library of uncertainties of radioactive decay data in the ABBN data library format are described. Different evaluations of uncertainties were compared and their effects on the results of calculations of residual energy release were determined using the test problems and experiment. Tables were generated in the ABBN format with the data obtained on the basis of libraries in ENDF-6 format. 3821 isotopes from the ENDF/B-7 data library, 3852 isotopes from the JEFF-3.11 data library and 1264 isotopes from the JENDL-4.0 data library were processed. It was revealed that the differences in the evaluations accepted in different decay data libraries are not so big, although they sometimes exceed the uncertainties assigned to the data in the ENDF/B-7 and JEFF-3.11 libraries, which as a rule, they agree with each other. On the basis of developed method it is supposed to create a library of data uncertainties for radioactive decay within the constant data system in FSUE RFNC-VNIIEF with its further connection with CRYSTAL module. (paper)

ROOTS: a program to generate radionuclide decay chains

International Nuclear Information System (INIS)

Fields, D.E.; Dunning, D.E. Jr.

1985-11-01

A set of algorithms has been developed to support dosimetric and transport calculations. These subroutines read a radionuclide data file and prepare a decay chain showing branching fractions and radioactive half-lives of each member. One application of these subroutines has been their implementation as a set of FORTRAN subroutines for application in the PREREM code (Ryan and Fields, 1981). Recent use of these subroutines in stand-alone form required their expansion to print branching fractions. An expanded data set based on ICRP-38 radionuclide data (ICRP, 1983) was also prepared. This subroutine package is called Radionuclide Origin and Ontogeny Tracing Subroutines (ROOTS). The package is intended for execution on a Digital Equipment Corporation PDP-10 Computer System, and may require modification to run on other machines. 6 refs

An experiment on radioactive equilibrium and its modelling using the ‘radioactive dice’ approach

Science.gov (United States)

Santostasi, Davide; Malgieri, Massimiliano; Montagna, Paolo; Vitulo, Paolo

2017-07-01

In this article we describe an educational activity on radioactive equilibrium we performed with secondary school students (17-18 years old) in the context of a vocational guidance stage for talented students at the Department of Physics of the University of Pavia. Radioactive equilibrium is investigated experimentally by having students measure the activity of 214Bi from two different samples, obtained using different preparation procedures from an uraniferous rock. Students are guided in understanding the mathematical structure of radioactive equilibrium through a modelling activity in two parts. Before the lab measurements, a dice game, which extends the traditional ‘radioactive dice’ activity to the case of a chain of two decaying nuclides, is performed by students divided into small groups. At the end of the laboratory work, students design and run a simple spreadsheet simulation modelling the same basic radioactive chain with user defined decay constants. By setting the constants to realistic values corresponding to nuclides of the uranium decay chain, students can deepen their understanding of the meaning of the experimental data, and also explore the difference between cases of non-equilibrium, transient and secular equilibrium.

Nuclear structure from radioactive decay

International Nuclear Information System (INIS)

Wood, J.L.

1991-01-01

This report discusses nuclear structure from radioactive decay of the following: Neutron-Deficient Iridium Isotopes; Neutron-Deficient Platinum Isotopes; Neutron-Deficient Gold Isotopes; Neutron-Deficient Mercury Isotopes; Neutron-Deficient Thallium Isotopes; Neutron-Deficient Lead Isotopes; Neutron-Deficient Samarium Isotopes; Neutron-Deficient Promethium Isotopes; Neutron-Deficient Neodymium Isotopes; and Neutron-Deficient Praseodymium Isotopes. Also discussed are Nuclear Systematics and Models

α decay chains in 271-294115 superheavy nuclei

International Nuclear Information System (INIS)

Santhosh, K. P.; Priyanka, B.; Joseph, Jayesh George; Sahadevan, Sabina

2011-01-01

α decay of 271-294 115 superheavy nuclei is studied using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The predicted α half-lives of 287 115 and 288 115 nuclei and their decay products are in good agreement with experimental values. Comparison of α and spontaneous fission half-lives predicts four-α chains and three-α chains, respectively, from 287 115 and 288 115 nuclei and are in agreement with experimental observation. Our study predicts two-α chains from 273,274,289 115, three-α chains from 275 115, and four-α chains consistently from 284,285,286 115 nuclei. These observations will be useful for further experimental investigation in this region.

Classification of decays involving variable decay chains with convolutional architectures

CERN Multimedia

CERN. Geneva

2018-01-01

Vidyo contribution We present a technique to perform classification of decays that exhibit decay chains involving a variable number of particles, which include a broad class of $B$ meson decays sensitive to new physics. The utility of such decays as a probe of the Standard Model is dependent upon accurate determination of the decay rate, which is challenged by the combinatorial background arising in high-multiplicity decay modes. In our model, each particle in the decay event is represented as a fixed-dimensional vector of feature attributes, forming an $n \\times k$ representation of the event, where $n$ is the number of particles in the event and $k$ is the dimensionality of the feature vector. A convolutional architecture is used to capture dependencies between the embedded particle representations and perform the final classification. The proposed model performs outperforms standard machine learning approaches based on Monte Carlo studies across a range of variable final-state decays with the Belle II det...

α -decay chains of superheavy nuclei with Z =125

Science.gov (United States)

Santhosh, K. P.; Nithya, C.

2018-04-01

The decay properties of the isotopes of Z =125 within the range 303 ≤ A ≤ 339 are investigated. The calculation of proton separation energies reveals that isotopes 125-309303 may decay through proton emission. Four different mass tables are used to show the sensitivity of the mass models used to calculate the Q values as well as the α-decay half-lives. α -decay chains are predicted by comparing the α half-lives calculated within the Coulomb and proximity potential model for deformed nuclei (CPPMDN) [Nucl. Phys. A 850, 34 (2011), 10.1016/j.nuclphysa.2010.12.002] with the spontaneous fission half-lives using the shell-effect-dependent formula [Phys. Rev. C 94, 054621 (2016), 10.1103/PhysRevC.94.054621]. It is seen that isotopes 125,311310 show 6α chains. 5α chains can be seen from isotopes 125-318312. Isotopes 125,320319 exhibit 2α chains and 323125 exhibits 1α chain. All the other isotopes, that is, 125 321 ,322 ,324 -339 may decay through spontaneous fission. The α half-lives using CPPMDN are compared with five other theoretical formalisms and are seen to be matching with each other. We hope that our studies will be helpful in designing future experiments to explore the island of stability.

Selected spectroscopic results on element 115 decay chains

International Nuclear Information System (INIS)

Rudolph, D.; Forsberg, U.; Golubev, P.; Sarmiento, L.G.; Yakushev, A.; Andersson, L.L.; Di Nitto, A.; Duellmann, Ch.E.; Gates, J.M.; Gregorich, K.E.

2015-01-01

Thirty correlated α-decay chains were observed in an experiment studying the fusion-evaporation reaction 48 Ca + 243 Am at the GSI Helmholtzzentrum fuer Schwerionenforschung. The decay characteristics of the majority of these 30 chains are consistent with previous observations and interpretations of such chains to originate from isotopes of element Z = 115. High-resolution α-photon coincidence spectroscopy in conjunction with comprehensive Monte-Carlo simulations allow to propose excitation schemes of atomic nuclei of the heaviest elements, thereby probing nuclear structure models near the 'Island of Stability' with unprecedented experimental precision. (author)

Experimental investigation of statistical density function of decaying radioactive sources

International Nuclear Information System (INIS)

Salma, I.; Zemplen-Papp, E.

1991-01-01

The validity of the Poisson and the λ P(k) modified Poisson statistical density functions of observing k events in a short time interval is investigated experimentally in radioactive decay detection for various measuring times. The experiments to measure radioactive decay were performed with 89m Y, using a multichannel analyzer. According to the results, Poisson statistics adequately describes the counting experiment for short measuring times. (author) 13 refs.; 4 figs

Quantum mechanical look at the radioactive-like decay of metastable dark energy

Energy Technology Data Exchange (ETDEWEB)

Szydlowski, Marek [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Jagiellonian University, Mark Kac Complex Systems Research Centre, Krakow (Poland); Stachowski, Aleksander [Jagiellonian University, Astronomical Observatory, Krakow (Poland); Urbanowski, Krzysztof [University of Zielona Gora, Institute of Physics, Zielona Gora (Poland)

2017-12-15

We derive the Shafieloo, Hazra, Sahni and Starobinsky (SHSS) phenomenological formula for the radioactive-like decay of metastable dark energy directly from the principles of quantum mechanics. To this aim we use the Fock-Krylov theory of quantum unstable states. We obtain deeper insight on the decay process as having three basic phases: the phase of radioactive decay, the next phase of damping oscillations, and finally the phase of power-law decay. We consider the cosmological model with matter and dark energy in the form of decaying metastable dark energy and study its dynamics in the framework of non-conservative cosmology with an interacting term determined by the running cosmological parameter. We study the cosmological implications of metastable dark energy and estimate the characteristic time of ending of the radioactive-like decay epoch to be 2.2 x 10{sup 4} of the present age of the Universe. We also confront the model with astronomical data which show that the model is in good agreement with the observations. Our general conclusion is that we are living in the epoch of the radioactive-like decay of metastable dark energy which is a relict of the quantum age of the Universe. (orig.)

α -decay chains of superheavy Mt-279265 isotopes

Science.gov (United States)

Santhosh, K. P.; Nithya, C.

2017-10-01

The α -decay chains of the isotopes Mt-279265 are predicted by comparing the α half-lives calculated within the Coulomb and proximity potential model for deformed nuclei of Santhosh et al. [Nucl. Phys. A 850, 34 (2011)], 10.1016/j.nuclphysa.2010.12.002 with the spontaneous fission half-lives using the shell-effect-dependent formula of Santhosh and Nithya [Phys. Rev. C 94, 054621 (2016)], 10.1103/PhysRevC.94.054621. α half-lives also are calculated using different theoretical formalisms for comparison. The predicted half-lives and decay modes match well with the experimental results. The use of four different mass tables for calculating the α - decay energies indicates that the mass table of Wang et al. [Chin. Phys. C 41, 030003 (2017)], 10.1088/1674-1137/41/3/030003, which is based on the AME2016 atomic mass evaluation, is in better agreement with experimental results. The paper predicts long α chains from 265,267-269,271-273MT with half-lives within experimental limits. The isotopes 274-276,278Mt exhibit 2α chains followed by spontaneous fission. The 2α chain of 266Mt and the 4α chain of 270Mt end with electron capture. The isotopes Mt,279277 decay via spontaneous fission. We hope that the paper will open up new areas in this field.

Alpha-Photon Coincidence Spectroscopy Along Element 115 Decay Chains

Energy Technology Data Exchange (ETDEWEB)

Rudolph, D. [Lund Univ., Lund (Sweden); Forsberg, U. [Lund Univ., Lund (Sweden); Golubev, P. [Lund Univ., Lund (Sweden); Sarmiento, L. G. [Lund Univ., Lund (Sweden); Yakushev, A. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Andersson, L. -L. [Helmholtz Institute Mainz, Mainz (Germany); Di Nitto, A. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Dullmann, Ch. E. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Gates, J. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gregorich, K. E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gross, C. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herzberg, R. -D. [Univ. of Liverpool, Liverpool (United Kingdom); Hessberger, F. P. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz Institute Mainz, Mainz (Germany); Khuyagbaatar, J. [Helmholtz Institute Mainz, Mainz (Germany); Kratz, J. V. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Rykaczewski, K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schadel, M. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Japan Atomic Energy Agency, Tokai (Japan); Aberg, S. [Lund Univ., Lund (Sweden); Ackermann, D. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Block, M. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Brand, H. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Carlsson, B. G. [Lund Univ., Lund (Sweden); Cox, D. [Univ. of Liverpool, Liverpool (United Kingdom); Derkx, X. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Eberhardt, K. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Even, J. [Helmholtz Institute Mainz, Mainz (Germany); Fahlander, C. [Lund Univ., Lund (Sweden); Gerl, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Jager, E. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kindler, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Krier, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kojouharov, I. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Kurz, N. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Lommel, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Mistry, A. [Univ. of Liverpool, Liverpool (United Kingdom); Mokry, C. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Nitsche, H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Omtvedt, J. P. [Univ. of Oslo, Oslo (Norway); Papadakis, P. [Univ. of Liverpool, Liverpool (United Kingdom); Ragnarsson, I. [Lund Univ., Lund (Sweden); Runke, J. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Schaffner, H. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Schausten, B. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Thorle-Pospiech, P. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Torres, T. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Traut, T. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Trautmann, N. [Johannes Gutenberg-Univ. Mainz, Mainz (Germany); Turler, A. [Paul Scherrer Institute and Univ. of Bern, Villigen (Switzerland); Ward, A. [Univ. of Liverpool, Liverpool (United Kingdom); Ward, D. E. [Lund Univ., Lund (Sweden); Wiehl, N. [Helmholtz Institute Mainz, Mainz (Germany); Johannes Gutenberg-Univ. Mainz, Mainz (Germany)

2014-01-01

Produced in the reaction ⁴⁸Ca+ ²⁴³Am, thirty correlated α-decay chains were observed in an experiment conducted at the GSI Helmholzzentrum für Schwerionenforschung, Darmstadt, Germany. The decay chains are basically consistent with previous findings and are considered to originate from isotopes of element 115 with mass numbers 287, 288, and 289. A set-up aiming specifically for high-resolution charged particle and photon coincidence spectroscopy was placed behind the gas-filled separator TASCA. For the first time, γ rays as well as X-ray candidates were observed in prompt coincidence with the α-decay chains of element 115.

The deterministic computational modelling of radioactivity

International Nuclear Information System (INIS)

Damasceno, Ralf M.; Barros, Ricardo C.

2009-01-01

This paper describes a computational applicative (software) that modelling the simply radioactive decay, the stable nuclei decay, and tbe chain decay directly coupled with superior limit of thirteen radioactive decays, and a internal data bank with the decay constants of the various existent decays, facilitating considerably the use of program by people who does not have access to the program are not connected to the nuclear area; this makes access of the program to people that do not have acknowledgment of that area. The paper presents numerical results for typical problem-models

Moderation of the 119mSn isomer radioactive decay

International Nuclear Information System (INIS)

Godovikov, S.K.

1999-01-01

The evaluation of the constant of the braked 119m Sn nuclei decay in the Moessbauer source, being for a long time in contact with a resonance shield, is carried out. The high stability of these nuclei relative to decay is established. The 119m Sn subjected to prolonged impact of the standing electromagnetic wave field become resistant to radioactive decay [ru

Agency practice and future policy in decay storage of radioactive wastes

International Nuclear Information System (INIS)

Mitchell, N.G.

2002-01-01

The Environment Agency issues authorisations under the Radioactive Substances Act 1993 for the accumulation of radioactive waste at non-nuclear sites prior to disposal. Radioactive decay during the accumulation period reduces the radioactive content of waste packages and provides a waste management option that has become known as decay-in-storage or decay storage. The project brief excluded nuclear licensed sites. A database of information in authorisations and application forms has been constructed. This information has been used alongside a literature review, international contacts, input from the Small Users Liaison Group and a dose assessment to look at the practice of decay storage. The basic principles behind decay storage are presented with specific sections on general safety, waste characterisation and segregation, storage containers, waste stores, and waste treatment and conditioning. The regulatory approach in seven other countries is described. The information collected from Agency public registers is summarised with particular attention given to storage periods of greater than 60 days and the corresponding information available from application forms. Operational experiences are presented. IAEA recommendations are compared with current practice based on the conditions found in authorisations, on the information from application forms and details provided by the Small Users Liaison Group

Force decay evaluation of thermoplastic and thermoset elastomeric chains: A mechanical design comparison.

Science.gov (United States)

Masoud, Ahmed I; Tsay, T Peter; BeGole, Ellen; Bedran-Russo, Ana K

2014-11-01

To compare the following over a period of 8 weeks: (1) force decay between thermoplastic (TP) and thermoset (TS) elastomeric chains; (2) force decay between light (200-g) and heavy (350-g) initial forces; and (3) force decay between direct chains and chain loops (stretched from one pin around the second pin and back to the first pin). TP and TS chains were obtained from American Orthodontics™ (AOTP, AOTS) and ORMCO™ (OrTP, OrTS). Each of the four chain groups was subdivided into four subgroups with 10 specimens per subgroup: (1) direct chains light force, (2) direct chains heavy force, (3) chain loops light force, and (4) chain loops heavy force. The experiment was performed in artificial saliva (pH of 6.75) at 37°C. A significant difference was found between TP and TS chains, with an average mean difference of around 20% more force decay found in the TP chains (P < .001, α  =  .05). There was no significant difference between direct chains and chain loops except in OrTP, in which direct chains showed more force decay. There was also no significant difference in force decay identified when using light vs heavy forces. TS chains decayed less than TP chains, and chain loop retraction was beneficial only when using OrTP chains. Contrary to the interchangeable use of TP and TS chains in the published literature and in clinical practice, this study demonstrates that they perform differently under stress and that a clear distinction should be made between the two.

Generating cryptographic keys by radioactive decays

International Nuclear Information System (INIS)

Grupen, Claus; Maurer, Ingo; Schmidt, Dieter; Smolik, Ludek

2001-01-01

We are presenting a new method for the generation of statistically genuine random bitstream with very high frequency which can be employed for cryptographic purposes. The method uses the feature of statistically unpredictable radioactive decays as the source of randomness. The measured quantity is the time distance between the responses of a small ionisation chamber due to the recording of ionising decay products. This time measurement is converted into states representing 0o r 1. The data generated in our experiment successfully passed FIPS PUB 140-1 and die hard statistical tests. For the simulation of systematic effects Monte Carlo techniques were used

Force decay of elastomeric chains - a mechanical design and product comparison study.

Science.gov (United States)

Balhoff, David A; Shuldberg, Matthew; Hagan, Joseph L; Ballard, Richard W; Armbruster, Paul C

2011-03-01

To evaluate the percentage force decay of elastomeric chain products utilizing three different design mechanisms simulating canine retraction; and to evaluate the percentage force decay of elastomeric chain products from four different companies. In vitro, laboratory study. LSUHSC Dental School, New Orleans, LA, USA. Closed (non-spaced), grey elastomeric chains from four companies were selected for the study. Three acrylic resin jigs were constructed to provide a framework for three simulated space closure mechanisms. The 6-5-3, the chain loop, and the 6-3 were the configuration mechanisms used in the study. An electronic force gauge was used to measure the percentage force decay associated with each elastomeric chain over 28 days at preselected times. There was a significant difference in the mean percentage force decay for the three different mechanisms (P < 0·001). For all four companies, the 6-3 mechanical design had the smallest mean percentage force decay. There was a significant difference in the mean percentage force decay for the different companies (P < 0·001). For all three mechanisms, Ormco had the smallest percentage force decay while Unitek had the highest percentage force decay. The significant difference in the mean percentage force decay for the different mechanisms suggests that the 6-3 design is a more efficient means of closing extraction spaces utilizing elastomeric chains.

Study on the transmutation of some radioactive wastes using the Bateman equations

International Nuclear Information System (INIS)

Orlandi, Horus Ibrahim; Moreira, Joao M.L.

2009-01-01

In this work, a numerical solution for the nuclear transmutation equations using the Bateman algorithm. The numerical solution was implemented using the JAVA language and the program gives the time variation of isotope chain decays population which appears due to nuclear transmutation. With the present results it is possible to understand the radioactive decay and the need of storage the radioactive decay along the years. The chain decay studied were the 99 Tc, 99 Zr, 135 Cs, 137 Cs and the 90 Sr, due to their long half-lives and the high fission yield

Decay times in one-dimensional chains

International Nuclear Information System (INIS)

Van den Broeck, C.; Bouten, M.

1986-01-01

The authors calculate the average residence time tau for a particle performing a random walk over a chain of N neighboring sites i = 1,..., N, with decay rates λ/sub i/ depending on the location of the particle in the chain. Exact results are given for some particular cases, while bounds on tau are given for specific initial conditions. In the continuum limit, various results from the literature are recovered or improved upon

DECSERVIS-2: A tool for natural decay series mass flow simulation

International Nuclear Information System (INIS)

Azzam, Saad; Suksi, Juhani; Ammann, Michael

2009-01-01

After the publication of 'DECSERVIS: a tool for radioactive decay series visualisation' we have further developed our DECSERVIS software. With the new tool DECSERVIS-2 one can simulate radioactive decay chains in open systems, i.e. when the concentrations of nuclides change also due to mass flows. Decay chains can be simulated under continuous and successive nuclide mass flow events into and out from the system and in freely determined time intervals. Simulation output for the entire decay chain (nuclide activity, mass, number of nuclides, nuclide ratios) can be presented as a function of time with various graphical presentations such as solid curve and column diagrams or animation. In this paper we introduce DECSERVIS-2 and demonstrate its use with simulation examples. DECSERVIS-2 is easy to use and has been designed with an eye on the demands of teaching.

Contaminant transport in fractured porous media: analytical solution for a two-member decay chain in a single fracture

International Nuclear Information System (INIS)

Sudicky, E.A.; Frind, E.O.

1984-01-01

An analytical solution is presented for the problem of radionuclide chain decay during transport through a discrete fracture situated in a porous rock matrix. The solution takes into account advection along the fracture, molecular diffusion from the fracture to the porous matrix, adsorption on the fracture face, adsorption in the rock matrix, and radioactive decay. The solution for the daughter product is in the form of a double integral which is evaluated by Gauss-Legendre quadrature. Results show that the daughter product tends to advance ahead of the parent nuclide even when the half-life of the parent is larger. This is attributed to the effect of chain decay in the matrix, which tends to reduce the diffusive loss of the daughter along the fracture. The examples also demonstrate that neglecting the parent nuclide and modeling its daughter as a single species can result in significant overestimation of arrival times at some point along the fracture. Although the analytical solution is restricted to a two-member chain for practical reasons, it represents a more realistic description of nuclide transport along a fracture than available single-species models. The solution may be of use for application to other contaminants undergoing different types of first-order transformation reactions

Analytical solution to the diffusion, sorption and decay chain equation in a saturated porous medium between two reservoirs

International Nuclear Information System (INIS)

Guzman, Juan; Maximov, Serguei; Escarela-Perez, Rafael; López-García, Irvin; Moranchel, Mario

2015-01-01

The diffusion and distribution coefficients are important parameters in the design of barrier systems used in radioactive repositories. These coefficients can be determined using a two-reservoir configuration, where a saturated porous medium is allocated between two reservoirs filled by stagnant water. One of the reservoirs contains a high concentration of radioisotopes. The goal of this work is to obtain an analytical solution for the concentration of all radioisotopes in the decay chain of a two-reservoir configuration. The analytical solution must be obtained by taking into account the diffusion and sorption processes. Concepts such as overvalued concentration, diffusion and decay factors are employed to this end. It is analytically proven that a factor of the solution is identical for all chains (considering a time scaling factor), if certain parameters do not change. In addition, it is proven that the concentration sensitivity, due to the distribution coefficient variation, depends of the porous medium thickness, which is practically insensitive for small porous medium thicknesses. The analytical solution for the radioisotope concentration is compared with experimental and numerical results available in literature. - Highlights: • Saturated porous media allocated between two reservoirs. • Analytical solution of the isotope transport equation. • Transport considers diffusion, sorption and decay chain

User's manual for the radioactive decay and accumulation code RADAC

International Nuclear Information System (INIS)

Salmon, R.; Loghry, S.L.; Ashline, R.C.

1995-11-01

The RADAC computer code calculates radioactive decay and accumulation of decayed products using an algorithm based on the direct use of the Bateman equations and referred to here as the yield factor method. This report explains the yield factor method, gives an overview of the various modules in the RADAC code system, and describes the decay and accumulation code in detail. The RADAC code has capacity for two waste types and can accommodate up to 60 years of annual waste inputs. Decay times as high as 1 million years can be calculated. The user supplies the undecayed composition and radioactivity of the waste placed in storage each year. The code calculates the decayed composition, radioactivity, and thermal power of the accumulated waste at the end of each year and gives the results in terms of grams and curies of individual radionuclides. Calculations can be made for up to 19 waste storage sites in a single run. For each site and each waste type, calculations can be made by 1-year steps up to 60 years, by 10-year steps to 160 years, and by 6 discrete steps to 1 million years. Detailed outputs can be printed for each waste site and each time step by individual radionuclides. Summarized outputs are also available. Excluding data-preparation time, RADAC requires about 2 min to run 19 waste sites with two types of transuranic waste at each site, using a 486 DX computer with a clock speed of 33 MHz. Because RADAC uses a preselected set of decay times and does not make in-reactor calculations, it should not be viewed as a substitute for ORIGEN2. RADAC is intended for use in applications in which accumulations at the decay times provided by the code are sufficient for the user's purposes

Simplifying the Mathematical Treatment of Radioactive Decay

Science.gov (United States)

Auty, Geoff

2011-01-01

Derivation of the law of radioactive decay is considered without prior knowledge of calculus or the exponential series. Calculus notation and exponential functions are used because ultimately they cannot be avoided, but they are introduced in a simple way and explained as needed. (Contains 10 figures, 1 box, and 1 table.)

General decay law for emission of charged particles and exotic cluster radioactivity

International Nuclear Information System (INIS)

Sahu, Basudeb; Paira, Ramkrishna; Rath, Biswanath

2013-01-01

For the emission of charged particles from metastable nuclei, a general decay formula is developed based on the basic phenomenon of resonances occurring in quantum scattering process under Coulomb-nuclear potential. It relates the half-lives of monopole radioactive decays with the Q-values of the outgoing elements in different angular momentum states as well as the masses and charges of the nuclei involved in the decay. The relation is found to be a generalization of the Geiger–Nuttall law in α radioactivity and it explains well all known emission of charged particles including clusters, alpha and proton carrying angular momenta

Limitations of Poisson statistics in describing radioactive decay.

Science.gov (United States)

Sitek, Arkadiusz; Celler, Anna M

2015-12-01

The assumption that nuclear decays are governed by Poisson statistics is an approximation. This approximation becomes unjustified when data acquisition times longer than or even comparable with the half-lives of the radioisotope in the sample are considered. In this work, the limits of the Poisson-statistics approximation are investigated. The formalism for the statistics of radioactive decay based on binomial distribution is derived. The theoretical factor describing the deviation of variance of the number of decays predicated by the Poisson distribution from the true variance is defined and investigated for several commonly used radiotracers such as (18)F, (15)O, (82)Rb, (13)N, (99m)Tc, (123)I, and (201)Tl. The variance of the number of decays estimated using the Poisson distribution is significantly different than the true variance for a 5-minute observation time of (11)C, (15)O, (13)N, and (82)Rb. Durations of nuclear medicine studies often are relatively long; they may be even a few times longer than the half-lives of some short-lived radiotracers. Our study shows that in such situations the Poisson statistics is unsuitable and should not be applied to describe the statistics of the number of decays in radioactive samples. However, the above statement does not directly apply to counting statistics at the level of event detection. Low sensitivities of detectors which are used in imaging studies make the Poisson approximation near perfect. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Modeling Radionuclide Decay Chain Migration Using HYDROGEOCHEM

Science.gov (United States)

Lin, T. C.; Tsai, C. H.; Lai, K. H.; Chen, J. S.

2014-12-01

Nuclear technology has been employed for energy production for several decades. Although people receive many benefits from nuclear energy, there are inevitably environmental pollutions as well as human health threats posed by the radioactive materials releases from nuclear waste disposed in geological repositories or accidental releases of radionuclides from nuclear facilities. Theoretical studies have been undertaken to understand the transport of radionuclides in subsurface environments because that the radionuclide transport in groundwater is one of the main pathway in exposure scenarios for the intake of radionuclides. The radionuclide transport in groundwater can be predicted using analytical solution as well as numerical models. In this study, we simulate the transport of the radionuclide decay chain using HYDROGEOCHEM. The simulated results are verified against the analytical solution available in the literature. Excellent agreements between the numerical simulation and the analytical are observed for a wide spectrum of concentration. HYDROGECHEM is a useful tool assessing the ecological and environmental impact of the accidental radionuclide releases such as the Fukushima nuclear disaster where multiple radionuclides leaked through the reactor, subsequently contaminating the local groundwater and ocean seawater in the vicinity of the nuclear plant.

Analytical method for solving radioactive transformations

International Nuclear Information System (INIS)

Vudakin, Z.

1999-01-01

Analytical method for solving radioactive transformations is presented in this paper. High accuracy series expansion of the depletion function and nonsingular Bateman coefficients are used to overcome numerical difficulties when applying well-known Bateman solution of a simple radioactive decay. Generality and simplicity of the method are found to be useful in evaluating nuclide chains with one hundred or more nuclides in the chain. Method enables evaluation of complete chain, without elimination of short-lives nuclides. It is efficient and accurate

Chemical aspects of the radioactive decay 38S to 38Cl

International Nuclear Information System (INIS)

Leurs, C.J.

1978-01-01

The cyclotron-production of 38 S with the reaction 40 Ar(p,3p) 38 S is described. An excitation curve for this nuclear reaction is given and the chemistry used to produce sulfates labeled with 38 S and H 2 38 S is described. The probability distribution of the recoil energy of 38 Cl, produced by beta-decay of 38 S, is given. The probability for rupture of the original bonds due to the radioactive decay process, is estimated for gaseous H 2 38 S and for crystalline sulfates- 38 S. The results are given for the β,γ-decay of 38 S to 38 Cl under different circumstances in inorganic solid sulfates (with and without water of crystallization) and in the mixed crystal K 2 SO 4 .K 2 BeF 4 (1 : 2500). Finally, the reactions of 38 Cl, produced by radioactive decay of 38 S (as H 2 38 S) with gaseous 1,2-dichloroethylene are discussed

Algebraic decay in self-similar Markov chains

International Nuclear Information System (INIS)

Hanson, J.D.; Cary, J.R.; Meiss, J.D.

1985-01-01

A continuous-time Markov chain is used to model motion in the neighborhood of a critical invariant circle for a Hamiltonian map. States in the infinite chain represent successive rational approximants to the frequency of the invariant circle. For the case of a noble frequency, the chain is self-similar and the nonlinear integral equation for the first passage time distribution is solved exactly. The asymptotic distribution is a power law times a function periodic in the logarithm of the time. For parameters relevant to the critical noble circle, the decay proceeds as t/sup -4.05/

Method for removal of decay heat of radioactive substances

International Nuclear Information System (INIS)

Hesky, H.; Wunderer, A.

1981-01-01

In this process, the decay heat from radioactive substances is removed by means of a liquid carried in the coolant loop. The liquid is partially evaporated by the decay heat. The steam is used to drive the liquid through the loop. When a static pressure level equivalent to the pressure drop in the loop is exceeded, the steam is separated from the liquid, condensed, and the condensate is reunited with the return flow of liquid for partial evaporation. (orig.) [de

Colloid-facilitated radionuclide transport in the fractured rock: effects of decay chain and limited matrix diffusion

International Nuclear Information System (INIS)

Park, J. B.; Park, J. W.; Lee, E. Y.; Kim, C. R.

2002-01-01

Colloid-facilitated radionuclide transport in the fractured rock is studies by considering radioactive decay chain and limited matrix diffusion into surrounding porous media. Semi-analytical solution in the Laplace domain is obtained from the mass balance equation of radionuclides and colloid particles. Numerical inversion of the Laplace solution is used to get the concentration profiles both in a fracture and in rock matrix. There issues are analyzed for the radionuclide concentration in a fracture by 1) formation constant of pseudo-colloid, 2) filtration coefficient of radio-colloid and 3) effective diffusion depth into the surrounding porous rock media

Algebraic decay in self-similar Markov chains

International Nuclear Information System (INIS)

Hanson, J.D.; Cary, J.R.; Meiss, J.D.

1984-10-01

A continuous time Markov chain is used to model motion in the neighborhood of a critical noble invariant circle in an area-preserving map. States in the infinite chain represent successive rational approximants to the frequency of the invariant circle. The nonlinear integral equation for the first passage time distribution is solved exactly. The asymptotic distribution is a power law times a function periodic in the logarithm of the time. For parameters relevant to Hamiltonian systems the decay proceeds as t -4 05

Computer simulation of the natural U 238 and U 235 radioactive series decay

International Nuclear Information System (INIS)

Barna, A.; Oncescu, M.

1980-01-01

The principles of the computer simulation of a radionuclide decay - its decay scheme adoption and codification -, and the adoption principle of a radionuclide chain in a series are applied to the natural U 238 and U 235 series radionuclide decay computer simulation. Using the computer simulation data of these two series adopted chains, the decay characteristic quantities of the series radionuclides, the gamma spectra and the basic characteristics of each of these series are determined and compared with the experimental values given in the literature. (author)

Photoluminescence decay lifetime measurements of hemicyanine derivatives of different alkyl chain lengths

International Nuclear Information System (INIS)

Shim, Taekyu; Lee, Myounghee; Kim, Sungho; Sung, Jaeho; Rhee, Bum Ku; Kim, Doseok; Kim, Hyunsung; Yoon, Kyung Byung

2004-01-01

The fluorescence upconversion setup for the detection of photoluminescence (PL) decay lifetime with subpicosecond time resolution was constructed, and the photoluminescence phenomena of several hemicyanine dyes with alkyl chains of different chain lengths tethered to the N atom of the pyridine moiety (HC-n, n=6, 15, 22) in methanol were investigated. The average decay lifetimes of the solutions determined from the measured data by multi-order exponential decay curve fitting were ∼27 ps at the PL peak wavelength. It was found that the PL decay properties did not depend on the alkyl chain length in the molecule, implying that the twist of the alkylpyridinium ring of the molecule is not possible as a nonfluorescing relaxation pathway. The time-dependent PL spectra constructed from the PL lifetime data showed the dynamic Stokes shift of ∼1000 cm -1

Radioactive decay data tables: a handbook of decay data for application to radiation dosimetry and radiological assessments

International Nuclear Information System (INIS)

Kocher, D.C.

1982-01-01

Reviews compendium containing recommended decay data for approx. 500 radionuclides of interest in nuclear medicine and fusion reactor technology or of potential importance in routine or accidental releases from the nuclear fuel cycle. Primary source of the decay data presented in this handbook is the Evaluated Nuclear Structure Data File (ENSDF), developed and maintained by the US Nuclear Data Network. Topics covered include various radioactive decay processes; evaluation process and standards of ENSDF; tables and computer code MEDLIST used to produce ENSDF tables; radiation dosimetry and radiological assessments; parent-daughter activity ratios wherever the adopted decay data may contain significant uncertainties or errors due to the lack of appropriate experimental data

Nuclear structure notes on element 115 decay chains

International Nuclear Information System (INIS)

Rudolph, D.; Sarmiento, L. G.; Forsberg, U.

2015-01-01

Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory

Nuclear structure notes on element 115 decay chains

Energy Technology Data Exchange (ETDEWEB)

Rudolph, D., E-mail: Dirk.Rudolph@nuclear.lu.se; Sarmiento, L. G.; Forsberg, U. [Department of Physics, Lund University, 22100 Lund (Sweden)

2015-10-15

Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory.

Natural radioactivity in food chains

Energy Technology Data Exchange (ETDEWEB)

Binnerts, W

1989-03-01

A number of longliving and still being produced radioactive isotopes produces well measurable and not to be neglected radiation, by which, via the food chains, plant, animal and man receives a socalled natural radiation dose. Six of the most important isotopes are discussed here. The radioisotopes /sup 14/C and /sup 40/K form part of the most live-necessary elements; they pass without strong enrichment and discrimination through the food chains and form a practically constant part of the living organism. Yet by excessive fertilizing a rather higher content of potassium than necessary is present in plants. Also a higher radiation dose arises from exessive uptake of food. The isotopes of uranium /sup 238/U and radium, /sup 226/Ra, discussed here, occur everywhere in the soil, but locally in very high amounts. They migrate for a very small part into plant and animal, sometimes occur in vegetable food as part of soil particles. Other important isotopes of the uranium families are radioactive lead, /sup 21/0Pb, and polonium, /sup 210/Po, which can be dispersed to a much greater amount than the other isotopes: in the form of the gaseous intermediate product radon, here the isotope /sup 222/Rn. /sup 210/Pb and /sup 210/Po are finally deposited upon plants and other food products. In the hydrosphere /sup 210/Po can be enriched in the food chain from plankton to fish. (author). 35 refs.; 2 figs.; 3 tabs.

Natural radioactivity in food chains

International Nuclear Information System (INIS)

Binnerts, W.

1989-01-01

A number of longliving and still being produced radioactive isotopes produces well measurable and not to be neglected radiation, by which, via the food chains, plant, animal and man receives a socalled natural radiation dose. Six of the most important isotopes are discussed here. The radioisotopes 14 C and 40 K form part of the most live-necessary elements; they pass without strong enrichment and discrimination through the food chains and form a practically constant part of the living organism. Yet by excessive fertilizing a rather higher content of potassium than necessary is present in plants. Also a higher radiation dose arises from exessive uptake of food. The isotopes of uranium 238 U and radium, 226 Ra, discussed here, occur everywhere in the soil, but locally in very high amounts. They migrate for a very small part into plant and animal, sometimes occur in vegetable food as part of soil particles. Other important isotopes of the uranium families are radioactive lead, 21 0Pb, and polonium, 210 Po, which can be dispersed to a much greater amount than the other isotopes: in the form of the gaseous intermediate product radon, here the isotope 222 Rn. 210 Pb and 210 Po are finally deposited upon plants and other food products. In the hydrosphere 210 Po can be enriched in the food chain from plankton to fish. (author). 35 refs.; 2 figs.; 3 tabs

A control volume scheme for three-dimensional transport: buffer and matrix effect on a decay chain transport in the repository

International Nuclear Information System (INIS)

Lee, Y. M.; Hwang, Y. S.; Kim, S. G.; Kang, C. H.

2002-01-01

Using a three-dimensional numerical code, B3R developed for nuclide transport of an arbitrary length of decay chain in the buffer between the canister and adjacent rock in a high-level radioactive waste repository by adopting a finite difference method utilizing the control-volume scheme, some illustrative calculations have been done. A linear sorption isotherm, nuclide transport due to diffusion in the buffer and the rock matrix, and advection and dispersion along thin rigid parallel fractures existing in a saturated porous rock matrix as well as diffusion through the fracture wall into the matrix is assumed. In such kind of repository, buffer and rock matrix are known to be important physico-chemical barriers in nuclide retardation. To show effects of buffer and rock matrix on nuclide transport in HLW repository and also to demonstrate usefulness of B3R, several cases of breakthrough curves as well as three-dimensional plots of concentration isopleths associated with these two barriers are introduced for a typical case of decay chain of 234 U→ 230 Th→ 226 Ra, which is the most important chain as far as the human environment is concerned

Solute transport in a single fracture involving an arbitrary length decay chain with rock matrix comprising different geological layers.

Science.gov (United States)

Mahmoudzadeh, Batoul; Liu, Longcheng; Moreno, Luis; Neretnieks, Ivars

2014-08-01

A model is developed to describe solute transport and retention in fractured rocks. It accounts for advection along the fracture, molecular diffusion from the fracture to the rock matrix composed of several geological layers, adsorption on the fracture surface, adsorption in the rock matrix layers and radioactive decay-chains. The analytical solution, obtained for the Laplace-transformed concentration at the outlet of the flowing channel, can conveniently be transformed back to the time domain by the use of the de Hoog algorithm. This allows one to readily include it into a fracture network model or a channel network model to predict nuclide transport through channels in heterogeneous fractured media consisting of an arbitrary number of rock units with piecewise constant properties. More importantly, the simulations made in this study recommend that it is necessary to account for decay-chains and also rock matrix comprising at least two different geological layers, if justified, in safety and performance assessment of the repositories for spent nuclear fuel. Copyright © 2014 Elsevier B.V. All rights reserved.

Alloy development for fast induced radioactivity decay for fusion reactor applications

International Nuclear Information System (INIS)

Klueh, R.L.; Bloom, E.E.

1984-01-01

During the operation of a fusion reactor, the structural material of the first wall and blanket structure will become highly radioactive from activation by the high-energy fusion neutrons. A difficult radioactive waste management problem will be involved in the disposal of this material after the service lifetime is complete. One way to minimize the management problem is the use of structural materials where the radioactive isotopes in the irradiated material decay to levels that allow for simplified disposal techniques. We are exploring how ferritic and austenitic steels could be developed to meet this objective

The Decay Data Evaluation Project (DDEP) and the JEFF-3.3 radioactive decay data library: Combining international collaborative efforts on evaluated decay data

Science.gov (United States)

Kellett, Mark A.; Bersillon, Olivier

2017-09-01

The Decay Data Evaluation Project (DDEP), is an international collaboration of decay data evaluators formed with groups from France, Germany, USA, China, Romania, Russia, Spain and the UK, mainly from the metrology community. DDEP members have evaluated over 220 radionuclides, following an agreed upon methodology, including a peer review. Evaluations include all relevant parameters relating to the nuclear decay and the associated atomic processes. An important output of these evaluations are recommendations for new measurements, which can serve as a basis for future measurement programmes. Recently evaluated radionuclides include: 18F, 59Fe, 82Rb, 82Sr, 88Y, 90Y, 89Zr, 94mTc, 109Cd, 133Ba, 140Ba, 140La, 151Sm and 169Er. The DDEP recommended data have recently been incorporated into the JEFF-3.3 Radioactive Decay Data Library. Other sources of nuclear data include 900 or so radionuclides converted from the Evaluated Nuclear Structure Data File (ENSDF), 500 from two UK libraries (UKPADD6.12 and UKHEDD2.6), the IAEA Actinide Decay Data Library, with the remainder converted from the NUBASE evaluation of nuclear properties. Mean decay energies for a number of radionuclides determined from total absorption gamma-ray spectroscopy (TAGS) have also been included, as well as more recent European results from TAGS measurements performed at the University of Jyväskylä by groups from the University of Valencia, Spain and SUBATECH, the University of Nantes, France. The current status of the DDEP collaboration and the JEFF Radioactive Decay Data Library will be presented. Note to the reader: the pdf file has been changed on September 22, 2017.

Catalog of gamma-rays unplaced in radioactive decay schemes

International Nuclear Information System (INIS)

Narita, Tsutomu; Kitao, Kensuke.

1991-03-01

A catalog is made for gamma-rays emitted in decay of radioactive nuclides but not placed in their decay schemes. It consists of two tables. In Table 1, the number of these unplaced gamma-ray components by a nuclide is given together with the fraction of total intensity of these gamma-rays to that of all observed gamma-rays. In Table 2, the unplaced gamma-rays are arranged in order of increasing energy. Each line of this table contains the gamma-ray energy, intensity, nuclide identification, and energies and intensities of the most prominent gamma-rays from the decay of the radionuclides. This catalog is a compilation from Evaluated Nuclear Structure Data File (ENSDF) maintained by National Nuclear Data Center at Brookhaven National Laboratory, of at February 1990. (author)

The importance of the radioactive decay study on prospecting, research and plough of uranium

International Nuclear Information System (INIS)

Juliao, B.

1990-01-01

A radioactive decay series such as that of U-238 is said to be in a state of secular equilibrium when the number of atoms of each daughter being produced in the series is equal to the number of atoms of that daughter being lost be radioactive decay. When this condition exists, it is possible to determine the amount of the parent of the decay series by measuring the radiation from daughter element. Radioactive disequilibrium is quite a common occurrence in roll-front or sandstone-type uranium deposits. The reason is that uranium may be mobile when oxidized and daughter products formation lags behind. This leads to a distribution of radioelements wherein the daughter products (e.g. Bi - 214) are left behind, creating a daughter excess or parent-deficiency state, with strong gamma ray activity. Miners should receive from geologists a precise and sufficiently detailed geological report, including all the informations about disequilibrium problems of the uranium, deposits. (author)

Radioactive decay of the late-time light curves of GRB-SNe

Science.gov (United States)

Misra, Kuntal; Fruchte, Andrew Steven

2018-04-01

We present the late-time Hubble Space Telescope observations of two GRB associated supernovae, GRB 030329/SN 2003dh and XRF 060218/SN 2006aj. Using the multi-color data upto ˜ 320 days after the burst, we constrain the late-time decay nature of these supernovae. The decay rates of SN 2003dh are steeper than SN 2006aj. A comparison with two other GRB supernovae, GRB 980425/SN 1998bw and the supernova associated with XRF 020903, shows that the decay rates of SN 2003dh are similar to XRF 020903 and those of SN 2006aj are similar to SN 1998bw. The late-time decay rates are steeper than the 56Co?56Fe radioactive decay rate (0.0098 mag day-1) indicating that there is some leakage of gamma-rays.

PABLM, Doses from Radioactive Releases to Atmosphere and Food Chain

International Nuclear Information System (INIS)

Napier, B.A.; Kennedy, W.E. Jr.; Soldat, J.K.

1983-01-01

1 - Description of problem or function: PABLM calculates internal radiation doses to man from radionuclides in food products and external radiation doses from radionuclides in the environment. Radiation doses from radionuclides in the environment may be calculated from deposition on the soil or plants during an atmospheric or liquid release, or from exposure to residual radionuclides after the releases have ended. Radioactive decay is considered during the release, after deposition, and during holdup of food after harvest. The radiation dose models consider exposure to radionuclides deposited on the ground or crops from contaminated air or irrigation water, radionuclides in contaminated drinking water, aquatic foods raised in contaminated water, and radionuclides in bodies of water and sediments where people might fish, boat, or swim. For vegetation, the radiation dose model considers both direct deposition and uptake through roots. Doses may be calculated for either a maximum-exposed individual or for a population group. The program is designed to calculate accumulated radiation doses from the chronic ingestion of food products that contain radionuclides and doses from the external exposure to radionuclides in the environment. A first-year committed dose is calculated as well as an integrated dose for a selected number of years. 2 - Method of solution: A chain decay scheme including branching for transitions to and from isomeric states is used for radioactive decay. The equations for calculating internal radiation doses are derived from those given by the International Commission on Radio- logical Protection (ICRP) for body burdens and the maximum possible concentration (MPC) for each radionuclide. These doses are calculated as a function of radionuclide concentration in food products, ingestion rates, and a radionuclide-specific dose- commitment factor. Radiation doses from external exposure to contaminated water and soil are calculated using the basic assumption

Radioactive decay of sup(91m)Nb

International Nuclear Information System (INIS)

Lakshminarayana, V.; Venkataratnam, S.; Rao, B.V.T.; Narasimham, K.L.

1987-01-01

The radioactive decay of sup(91m)Nb, produced by the reaction 89 Y(α, 2n), is studied using Ge(Li), HPGe and Si(Li) detectors. The K-conversion coefficient, αsub(K), of the 104.5 keV transition is determined accurately, for the first time, from the Nb Ksub(α) x-ray and 104.5 keV gamma-ray intensities. The experimental value of αsub(K) thus determined is 115(5), in agreement with the value expected for an M4 transition. (author)

CINDER, Depletion and Decay Chain Calculation for Fission Products in Thermal Reactors

International Nuclear Information System (INIS)

England, T.R.; Gorrell, T.C.; Hightower, J.H.

2001-01-01

1 - Description of problem or function: CINDER is a four-group, one- point depletion and fission product program based on the evaluation of a general analytical solution of nuclides coupled in any linear sequence of radioactive decays and neutron absorptions in a specified neutron flux spectrum. The desired depletion and fission product chains and all physical data are specified by the problem originator. The program computes individual nuclide number densities, activities, nine energy-group disintegration rates, and macroscopic and barns/fission poisons at each time-step as well as selected summaries of these data. 2 - Method of solution: Time-dependent variations in nuclide cross sections and neutron fluxes are approximated by a user-specified sequential set of values which are considered constant during the duration of the user-specified associated time-increments. When a nuclide concentration is independent of the concentration of any of its progeny, it is possible to resolve the couplings so as to obtain nuclides fed by a single parent. These chains are referred to as linear. 3 - Restrictions on the complexity of the problem: The program is limited to 500 total nuclides formed in up to 240 chains of 20 or fewer nuclides each. Up to 10 nuclides may act as fission product sources, contributing to power, and as many as 99 time-steps of arbitrary length are permitted. All stable nuclides must have a cross section if zero power time-increments are anticipated

Radioactive decay of sup(91m)Nb

Energy Technology Data Exchange (ETDEWEB)

Lakshminarayana, V.; Venkataratnam, S.; Rao, B.V.T.; Narasimham, K.L.; Chintalapudi, S.N.

1987-08-01

The radioactive decay of sup(91m)Nb, produced by the reaction /sup 89/Y(..cap alpha.., 2n), is studied using Ge(Li), HPGe and Si(Li) detectors. The K-conversion coefficient, ..cap alpha..sub(K), of the 104.5 keV transition is determined accurately, for the first time, from the Nb Ksub(..cap alpha..) x-ray and 104.5 keV gamma-ray intensities. The experimental value of ..cap alpha..sub(K) thus determined is 115(5), in agreement with the value expected for an M4 transition.

Update and evaluation of decay data for spent nuclear fuel analyses

Science.gov (United States)

Simeonov, Teodosi; Wemple, Charles

2017-09-01

Studsvik's approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL) and processed (ESTAR) sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources). Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Update and evaluation of decay data for spent nuclear fuel analyses

Directory of Open Access Journals (Sweden)

Simeonov Teodosi

2017-01-01

Full Text Available Studsvik’s approach to spent nuclear fuel analyses combines isotopic concentrations and multi-group cross-sections, calculated by the CASMO5 or HELIOS2 lattice transport codes, with core irradiation history data from the SIMULATE5 reactor core simulator and tabulated isotopic decay data. These data sources are used and processed by the code SNF to predict spent nuclear fuel characteristics. Recent advances in the generation procedure for the SNF decay data are presented. The SNF decay data includes basic data, such as decay constants, atomic masses and nuclide transmutation chains; radiation emission spectra for photons from radioactive decay, alpha-n reactions, bremsstrahlung, and spontaneous fission, electrons and alpha particles from radioactive decay, and neutrons from radioactive decay, spontaneous fission, and alpha-n reactions; decay heat production; and electro-atomic interaction data for bremsstrahlung production. These data are compiled from fundamental (ENDF, ENSDF, TENDL and processed (ESTAR sources for nearly 3700 nuclides. A rigorous evaluation procedure of internal consistency checks and comparisons to measurements and benchmarks, and code-to-code verifications is performed at the individual isotope level and using integral characteristics on a fuel assembly level (e.g., decay heat, radioactivity, neutron and gamma sources. Significant challenges are presented by the scope and complexity of the data processing, a dearth of relevant detailed measurements, and reliance on theoretical models for some data.

Simulation of decay processes and radiation transport times in radioactivity measurements

Energy Technology Data Exchange (ETDEWEB)

García-Toraño, E., E-mail: e.garciatorano@ciemat.es [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Peyres, V. [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Bé, M.-M.; Dulieu, C.; Lépy, M.-C. [CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), Bldg 602, PC111, 91191 Gif-sur-Yvette Cedex (France); Salvat, F. [Facultat de Física (FQA and ICC), Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain)

2017-04-01

The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

Some discussions on micrometeorology and atmospheric diffusion of classic and radioactive industrial pollutions. 6

International Nuclear Information System (INIS)

Veverka, O.; Valenta, V.; Vlachovsky, K.

1976-01-01

Plume depletion and deposition is discussed for the cases of stack disposal of conventional and radioactive wastes. Dry and wet deposition processes and general radioactive decay chains including isomeric transitions are taken into account. (author)

Radioactive decay pattern of actinides present in waste from Mo-99 production

Energy Technology Data Exchange (ETDEWEB)

Hiromoto, Goro; Dellamano, José Claudio, E-mail: hiromoto@ipen.br, E-mail: jcdellam@ipen.br [Instituto de PesquisasEnergéticas e Nucleares (GRR/IPEN/CNEN-SP), São Paulo, SP (Brazil). Gerência de Rejeitos Radioativos

2017-07-01

Brazil is currently planning to produce {sup 99}Mo from fission of LEU targets to meet the present national demand of {sup 99m}Tc. The {sup 99}Mo activity planned at the end of irradiation is 5000 Ci (185 TBq) per weekly cycle, in order to meet the present demand of 1000 Ci (37 TBq) per week, after target cooling and processing. To predict the activities that will be handled in the waste treatment facility, the computational code SCALE 6.0 was used to simulate the irradiation of the uranium targets and the decay of radioactive products. This study presents the findings of this research, mainly focused on the actinides activity that will be present in the waste and the respective radioactive decay pattern over a period of one hundred thousand years. (author)

Ground state properties of new element Z=113 and its alpha decay chain

International Nuclear Information System (INIS)

Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou

2005-01-01

The authors investigate the ground state properties of the new element 278 113 and of the α-decay chain with different models, where the new element Z=113 has been produced at RIKEN in Japan by cold-fusion reaction. The experimental decay energies are reproduced by the deformed relativistic mean-field model, by the Skyrme-Hartree-Fock (SHF) model, and by the macroscopic-microscopic model. Theoretical half-lives also reasonably agree with the data. Calculations further show that prolate deformation is important for the ground states of the nuclei in the α-decay chain of 278 113. The common points and differences among different models are compared and discussed. (author)

Structure effects in the region of superheavy elements via the α-decay chain of 293118

International Nuclear Information System (INIS)

Gupta, Raj K; Kumar, Sushil; Kumar, Rajesh; Balasubramaniam, M; Scheid, W

2002-01-01

The α-decay chain of 293 118, first proposed in the Berkeley cold fusion experiment 208 Pb( 86 Kr, 1n) and now retracted, is calculated by using the preformed cluster model (PCM) of one of the authors (RKG). Also, the possible branchings of α-decays to heavier cluster decays of all the parents in this chain are calculated for the first time. The calculated Q-values, penetrabilities and preformation factors for α-decays suggest that the 285 114 nucleus with Z=114, N=171 is a magic nucleus, either due to the magicity of Z=114, or N=172 or both. The N=172 is proposed to be a magic number in certain relativistic mean-field calculations, but with Z 120. The calculated cluster decays point to new interesting possibilities of 14 C decay of the 281 112 parent, giving rise to a (reasonably) deformed Z=106, N=161, 267 106 daughter (N=162 being now established as the deformed magic shell) or to a doubly magic 48 Ca cluster emitted from any of the parent nucleus in the α-decay chain. Apparently, these are exciting new directions for future experiments

Observation of Two-Proton Radioactivity of 19Mg by Tracking the Decay Products

International Nuclear Information System (INIS)

Mukha, I.; Alvarez, M. A. G.; Espino, J.; Gomez-Camacho, J.; Suemmerer, K.; Chatillon, A.; Geissel, H.; Hoffmann, J.; Kurz, N.; Litvinov, Yu.; Nociforo, C.; Ott, W.; Roeckl, E.; Weick, H.; Acosta, L.; Garcia-Ramos, J. E.; Martel, I.; Casarejos, E.; Cortina-Gil, D.; Rodriguez-Tajes, C.

2007-01-01

We have observed the two-proton radioactivity of the previously unknown 19 Mg ground state by tracking the decay products in-flight. For the first time, the trajectories of the 2p-decay products, 17 Ne+p+p, have been measured by using tracking microstrip detectors which allowed us to reconstruct the 2p-decay vertices and fragment correlations. The half-life of 19 Mg deduced from the measured vertex distribution is 4.0(15) ps in the system of 19 Mg. The Q value of the 2p decay of the 19 Mg ground state inferred from the measured p-p- 17 Ne correlations is 0.75(5) MeV

Concentration of radioactive cobalt by seaweeds in the food chain

International Nuclear Information System (INIS)

Nakahara, Motokazu; Koyanagi, Taku; Saiki, Masamichi

1976-01-01

On the pathway of radioactive substances in marine environments, seaweeds play an important role because of their higher concentration factors for many radionuclides and because they constitute a link of food chain in the sea. In the present work, uptake, distribution and excretion of radioactive cobalt were studied on several kinds of seaweeds by radioisotope tracer experiments under laboratory conditions and concentration factors were calculated. The concentration factors were also estimated from the results of stable cobalt determination by activation analysis or atomic absorption spectrometry on seaweeds and seawater, and compared with the results of tracer expts. The seaweeds showed the species specificity for the concentration of stable and radioactive cobalt with diverse values of concentration factors and biological half-lives. The transfer of radioactive cobalt in the food chain from contaminated seaweeds to mollusca was examined by feeding abalones, Haliotis discus, with four kinds of seaweed labelled with 60 Co and observing retention. Absorption rate for radioactive cobalt by abalones calculated at two days after feeding showed diverse values depending upon the species of seaweed, as follows: 47% through Laminaria japonica and Ulva pertusa, 31% through Undaria pinnatifida and 26 through Eisenia bicyclis, respectively. From the results, it was assumed that the accumulation of radioactive cobalt by mollusca is affected by the species of seaweeds as food. A very high concentration of ingested radioactive cobalt in the midgut gland was seen on the autoradiograph of abalone samples. (auth.)

Concentration of radioactive cobalt by seaweeds in the food chain

International Nuclear Information System (INIS)

Nakahara, M.; Koyanagi, T.; Saiki, M.

1975-01-01

On the pathway of radioactive substances in marine environments, seaweeds play an important role because of their higher concentration factors for many radionuclides and because they constitute a link in the food chain. In the present work, uptake, distribution and excretion of radioactive cobalt were studied on several kinds of seaweeds by radioisotope tracer experiments under laboratory conditions and concentration factors were calculated. The concentration factors were also estimated from the results of stable cobalt determination by activation analysis or atomic absorption spectrometry on seaweeds and seawater, and compared with the results of tracer experiments. The seaweeds showed the species specificity for the concentration of stable and radioactive cobalt with diverse values of concentration factors and biological half-lives. The transfer of radioactive cobalt in the food chain from contaminated seaweeds to mollusca was examined by feeding abalones, Haliotis discus, with four kinds of seaweed labelled with 60 Co and observing retention. Absorption rate for radioactive cobalt by abalones calculated at two days after feeding showed diverse values depending upon the species of seaweed, as follows: 47% through Laminaria japonica and Ulva pertusa, 31% through Undaria pinnatifida and 26% through Eisenia bicyclis, respectively. From the results, it was assumed that the accumulation of radioactive cobalt by mollusca is affected by the species of seaweeds as food. A very high concentration of ingested radioactive cobalt in the midgut gland was seen on the autoradiograph of abalone samples. (author)

Use of MICRAS code on the evaluation of the maximum radionuclides concentrations due to transport/migration of decay chain in groundwaters

International Nuclear Information System (INIS)

Aquino Branco, O.E. de

1995-01-01

This paper presents a methodology for the evaluation of the maximum radionuclides concentrations in groundwaters, due to the transport/migration of decay chains. Analytical solution of the equations system is difficult, even if only three elements of the decay chain are considered. Therefore, a numerical solution is most convenient. An application of the MICRAS code, developed to assess maximum concentrations of each radionuclide, starting with the initial concentrations, is presented. The maximum concentration profile for 226 Ra, calculated using MICRAS, is compared with the results obtained through an analytical and a numerical model. The fitness of results is considered good. Simplified models, like the one represented by the application of MICRAS, are largely employed in the section in the selection and characterization of sites for radioactive wastes repositories and in studies of safety evaluation for the same purpose. A detailed analysis of the transport/migration of contaminants in aquifers requires a large quantify of data from the site and from the installation as well, which makes this analysis expensive and inviable during the preliminary phases of the studies. (author). 6 refs, 1 fig, 1 tab

Radioactive decay of 223Ra by 14C emission

International Nuclear Information System (INIS)

Yashita, S.; Gregorich, K.; Ghiorso, A.

1985-01-01

Recently H.J. Rose and G.A. Jones at the University of Oxford reported the very difficult observation of an exotic radioactive decay mode in 233 Ra, its spontaneous disintegration by the emission of 14 C particles. The authors have confirmed their somewhat surprising discovery by an independent method. Within the present experimental accuracy the magnetic rigidity, energy and branching ratio support the assignment of 14 C emission from 223 Ra as proposed by the Oxford experiment

Effect of chemical structure on the radioactive decay rate of 71Ge

International Nuclear Information System (INIS)

Makariunas, K.; Makariuniene, E.; Dragunas, A.

1979-01-01

The influence of the chemical structure on the electron capture radioactive decay rate of 71 Ge was observed. 71 Ge nuclei in bivalent sulphide GeS decay faster than in quadrivalent sulphide GeS 2 . The relative change Δlambda/lambda of the decay constant lambda is + (11.4 +- 1.7) X 10 -4 . A possibility to use the experimental values of Δlambda/lambda to determine the chemical changes in the electron density at germanium nuclei in germanium chemical compounds is discussed. Quantitative determination of the changes in the electron density is complicated because of insufficient reliability of the published values of exchange and overlap corrections to the electron capture probabilities. (Auth.)

Mining of Radioactive Raw Materials as an Origin of the Nuclear Fuel Chain

Directory of Open Access Journals (Sweden)

Bedřich Michálek

2007-01-01

Full Text Available The mining of radioactive raw materials may be considered as an origin of the nuclear fuel chain and thus determines the amount of radioactive wastes which have to be stored safety in the final stage of the fuel chain. The paper informs about the existing trends in mining of radioactive raw materials in the world, provides an overview of development in mining in the Czech Republic and of possibilities of future exploiting some uranium deposits. It points a possibility of non-traditional obtaining uranium from mine waters from underground uranium mines closed and flooded earlier.

Simultaneous resolution of reactive radioactive decay, non-isothermal flow, and migration with application to the performance assessment for HLW repositories

International Nuclear Information System (INIS)

Juncosa, R.; Delgado, J.; Font, I.

2010-01-01

Radioactive decay is an important subject to take into account when studying the thermo-hydro-dynamic behavior of the buffer clay material used in the containment of radioactive waste. The modern concepts for the multibarrier design of a repository of high level waste in deep geologic formations consider that once canisters have failed, the buffer clay material must ensure the retention and/or delay of radionuclides within the time framework given in the assessment studies. Within the clay buffer, different chemical species are retarded/fixed according to several physicochemical processes (ion exchange, surface complexation, precipitation, matrix diffusion,..) but typical approaches do not consider the eventuality that radioactive species change their chemical nature (i.e. phase) thereby affecting their reactive behavior. The radioactive decay of an element takes place independently of the phase (aqueous, solid or gaseous) to which it belongs. This means that, in terms of radionuclide fixation, some geochemical processes will be effective scavengers (for instance mineral precipitation of crystal growth) while others will not (for instance ion exchange and/or sorption). In this contribution we present a reactive radioactive decay model of any number of chemical components including those that belong to decay series. The model, which is named FLOW-DECAY, also takes into account flow and isotopic migration and it has been applied considering a hypothetical model scenario provided by the project ENRESA 2000 and direct comparison with the results generated by the probabilistic code GoldSim. Results indicate that FLOW-DECAY may simulate the decay processes in a similar way that GoldSim, being the differences related to factors associated to code architecture. (orig.)

Spinon decay in the spin-1/2 Heisenberg chain with weak next nearest neighbour exchange

International Nuclear Information System (INIS)

Groha, Stefan; Essler, Fabian H L

2017-01-01

Integrable models support elementary excitations with infinite lifetimes. In the spin-1/2 Heisenberg chain these are known as spinons. We consider the stability of spinons when a weak integrability breaking perturbation is added to the Heisenberg chain in a magnetic field. We focus on the case where the perturbation is a next nearest neighbour exchange interaction. We calculate the spinon decay rate in leading order in perturbation theory using methods of integrability and identify the dominant decay channels. The decay rate is found to be small, which indicates that spinons remain well-defined excitations even though integrability is broken. (paper)

α-decay chain and associated cluster emission from neutron deficient 237Cf nucleus

International Nuclear Information System (INIS)

Jain, Deepika; Sharma, Manoj K.

2015-01-01

We have studied the α-decay chain of 237 Cf nucleus, which has been observed in the 3n evaporation channel when the semi-magic projectile 36 S strikes on 204 Pbv nucleus. The calculations are carried out by using preformed cluster model (PCM), with choices of spherical and quadruple deformation with in cold optimum orientation approach. The calculated half-lives of α-decay chain find relatively in nice agreement with experimental data for the deformed fragmentation approach. Along with α emission, the possibility of heavier clusters is also worked out and corresponding half-lives are predicted. (author)

Development of probabilistic assessment methodology for geologic disposal of radioactive wastes

International Nuclear Information System (INIS)

Kimura, H.; Takahashi, T.

1998-01-01

The probabilistic assessment methodology is essential to evaluate uncertainties of long-term radiological consequences associated with geologic disposal of radioactive wastes. We have developed a probabilistic assessment methodology to estimate the influences of parameter uncertainties/variabilities. An exposure scenario considered here is based on a groundwater migration scenario. A computer code system GSRW-PSA thus developed is based on a non site-specific model, and consists of a set of sub modules for sampling of model parameters, calculating the release of radionuclides from engineered barriers, calculating the transport of radionuclides through the geosphere, calculating radiation exposures of the public, and calculating the statistical values relating the uncertainties and sensitivities. The results of uncertainty analyses for α-nuclides quantitatively indicate that natural uranium ( 238 U) concentration is suitable for an alternative safety indicator of long-lived radioactive waste disposal, because the estimated range of individual dose equivalent due to 238 U decay chain is narrower that that due to other decay chain ( 237 Np decay chain). It is internationally necessary to have detailed discussion on the PDF of model parameters and the PSA methodology to evaluated the uncertainties due to conceptual models and scenarios. (author)

Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay

International Nuclear Information System (INIS)

Prince, J.R.

1979-01-01

Equations describing serial radioactive decay are reviewed along with published descriptions or transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium

Bioaccumulation and food chain transfer of corrosion products from radioactive stainless steel

International Nuclear Information System (INIS)

Young, J.S.

1986-07-01

Two sets of experiments were conducted to determine if corrosion products from radioactive Type 347 stainless steel could be biologically transferred from sediment through a marine food chain, and whether corrosion products dissolved in seawater could be bioaccumulated and then eliminated. Corrosion products containing 60 Co and 63 Ni from the radioactive stainless steel were introduced into marine sediments. Infaunal polychaete worms exposed to these sediments bioaccumulated the radionuclides. The feeding of these worms to shrimp and fish resulted in a trophic transfer of the radioactive products across a one-step food chain. The magnitude of the transfers are described in terms of transfer factors. Dissolved corrosion products as measured by the radionuclides were also bioaccumulated by shrimp and fish concentrating more than fish. Concentration factors were calculated

Diffusion of radionuclide chains through an adsorbing medium

International Nuclear Information System (INIS)

Burkholder, H.C.; DeFigh-Price, C.

1977-01-01

The diffusion of radionuclide chains from an underground nuclear waste disposal site through the surrounding geologic medium to the surface is investigated for impulse and band releases. Numerical calculation of the analytical solutions shows that differences in adsorption characteristics among chain members and radioactive decay during transit reduce radionuclide discharges to the biosphere. Results suggest that molecular diffusion is unlikely to be an important transfer mechanism from geologic isolation, and that disposal of radionuclides in deep geologic formations and in the seabed under conditions of very low or nonexistent water flow is likely to be very effective in preventing radioactivity releases to the biosphere

Spin correlations in decay chains involving W bosons

International Nuclear Information System (INIS)

Smillie, J.M.

2007-01-01

We study the extent to which spin assignments of new particles produced at the LHC can be deduced in the decay of a scalar or fermion C into a new stable (or quasi-stable) particle A through the chain C→B ± q, B ± →AW ± , W ± →l ± ν l where l=e,μ. All possible spin assignments of the particles A and B are considered. Explicit invariant mass distributions of the quark and lepton are given for each set of spins, valid for all masses. We also construct the asymmetry between the chains with a W - and those with a W + . The Kullback-Leibler distance between the distributions is then calculated to give a quantitative measure of our ability to distinguish the different spin assignments. (orig.)

Reactivity effects of fission product decay in PWRs

International Nuclear Information System (INIS)

Aragones, J.M.; Ahnert, C.

1988-01-01

The purpose of the work reported in this paper is to analyze the effects of fission product chains with radioactive decay on the reactivity in pressurized water reactor (PWR) cores, calculating their accumulation and absorption rates along fuel burnup at continuous operation and after shutdown periods extending from 1 day to a few months. The authors PWR version of the WIMS-D4 code is first used to obtain the individual number densities, absorption rates, and averaged cross sections for every nuclide of the fission product chains with significant decay rates, as a function of fuel burnup at continuous irradiation. Next, by an auxiliary ad hoc code, these data, have been processed together with the required one for fissile nuclides and boron, also taken from WIMS at each burnup step, to calculate the average or effective values relevant for the analysis and the decay and change in overall absorption after several shutdown times. (1) The reactivity effect of fission product decay changes significantly with the shutdown time. The maximum absorption increase by decay is reached in ∼ 10 days' shutdown. (2) The dependence with fuel type, enrichment, and burnup is slight, but the change with previous power density is nearly linear, which might be significant after coast-down in previous cycles. (3) For long shutdown periods, the overall reactivity effect of decay in the three fission product chains considered is much less than if only the samarium peak due to 149 Nd is considered

R and D on the Geant4 radioactive decay physics

Energy Technology Data Exchange (ETDEWEB)

Hauf, Steffen; Kuster, Markus; Lang, Philipp M.; Hoffmann, Dieter H.H. [IKP, TU Darmstadt (Germany); Pia, Maria Grazia [CERN, Genf (Switzerland); INFN, Genua (Italy); Bell, Zane [Oak Ridge National Lab. (United States); Weidenspointner, Georg [MPI HLL, Muenchen (Germany); MPE, Garching (Germany); Zoglauer, Andreas [SSL, Berkeley (United States)

2010-07-01

The anticipated high sensitivity of the next generation X-ray space missions, like the International X-ray Observatory, rely on a low instrumental background, which in turn requires optimized shielding concepts for the instruments. Most state-of-the-art approaches estimate the prompt cosmic ray, solar proton and the cosmic X-ray induced background with simulations using the Geant4 Monte Carlo tool-kit whose electromagnetic and hadronic physics models have extensively been verified with space and ground based experiments. In contrast measurements to verify the radioactive decay implementation in Geant4 have been rare or have only been tested on a limited set of isotopes, which are not necessarily those used in satellite construction. We present first results of two experiments aimed to verify Geant4 activation and decay physics for materials significant for low background X-ray detectors in space.

Between atomic and nuclear physics: radioactive decays of highly-charged ions

International Nuclear Information System (INIS)

Atanasov, Dinko; Bosch, Fritz; Brandau, Carsten; Chen, Xiangcheng; Dillmann, Iris; Gao, Bingshui; Geissel, Hans; Hagmann, Siegbert; Hillenbrand, Pierre-Michel; Kozhuharov, Christophor; Litvinov, Sergey A; Litvinov, Yuri A; Münzenberg, Gottfried; Blaum, Klaus; Bühler, Paul; Faestermann, Thomas; Gernhäuser, Roman; Izumikawa, Takuji; Kurcewicz, Jan; Ma, Xinwen

2015-01-01

Highly charged radioactive ions can be stored for extended periods of time in storage rings which allows for precision measurements of their decay modes. The straightforward motivation for performing such studies is that fully ionised nuclei or few-electron ions can be viewed as clean quantum-mechanical systems, in which the interactions of the many electrons can be either excluded or treated precisely. Thus, the influence of the electron shell on the decay probability can be investigated. Another important motivation is stellar nucleosynthesis, which proceeds at high temperatures and the involved atoms are therefore highly ionised. Presented here is a compact review of the relevant experiments conducted at heavy-ion storage rings. Furthermore, we outline the perspectives for future experiments at new-generation storage-ring facilities. (paper)

Decay tank

International Nuclear Information System (INIS)

Matsumura, Seiichi; Tagishi, Akinori; Sakata, Yuji; Kontani, Koji; Sudo, Yukio; Kaminaga, Masanori; Kameyama, Iwao; Ando, Koei; Ishiki, Masahiko.

1990-01-01

The present invention concerns an decay tank for decaying a radioactivity concentration of a fluid containing radioactive material. The inside of an decay tank body is partitioned by partitioning plates to form a flow channel. A porous plate is attached at the portion above the end of the partitioning plate, that is, a portion where the flow is just turned. A part of the porous plate has a slit-like opening on the side close to the partitioning plate, that is, the inner side of the flow at the turning portion thereof. Accordingly, the primary coolants passed through the pool type nuclear reactor and flown into the decay tank are flow caused to uniformly over the entire part of the tank without causing swirling. Since a distribution in a staying time is thus decreased, the effect of decaying 16 N as radioactive nuclides in the primary coolants is increased even in a limited volume of the tank. (I.N.)

Cluster radioactive decay within the preformed cluster model using relativistic mean-field theory densities

International Nuclear Information System (INIS)

Singh, BirBikram; Patra, S. K.; Gupta, Raj K.

2010-01-01

We have studied the (ground-state) cluster radioactive decays within the preformed cluster model (PCM) of Gupta and collaborators [R. K. Gupta, in Proceedings of the 5th International Conference on Nuclear Reaction Mechanisms, Varenna, edited by E. Gadioli (Ricerca Scientifica ed Educazione Permanente, Milano, 1988), p. 416; S. S. Malik and R. K. Gupta, Phys. Rev. C 39, 1992 (1989)]. The relativistic mean-field (RMF) theory is used to obtain the nuclear matter densities for the double folding procedure used to construct the cluster-daughter potential with M3Y nucleon-nucleon interaction including exchange effects. Following the PCM approach, we have deduced empirically the preformation probability P 0 emp from the experimental data on both the α- and exotic cluster-decays, specifically of parents in the trans-lead region having doubly magic 208 Pb or its neighboring nuclei as daughters. Interestingly, the RMF-densities-based nuclear potential supports the concept of preformation for both the α and heavier clusters in radioactive nuclei. P 0 α(emp) for α decays is almost constant (∼10 -2 -10 -3 ) for all the parent nuclei considered here, and P 0 c(emp) for cluster decays of the same parents decrease with the size of clusters emitted from different parents. The results obtained for P 0 c(emp) are reasonable and are within two to three orders of magnitude of the well-accepted phenomenological model of Blendowske-Walliser for light clusters.

$\\beta$-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

CERN Multimedia

We propose to study the $\\beta$-delayed fission, laser spectroscopy and radioactive decay of the newly available pure beams of neutron-deficient and neutron-rich astatine (Z=85) isotopes. The fission probability and the fission fragment distribution of the even-even isotopes $^{194,196}$Po following the $\\beta$-decay of the isotopes $^{194,196}$At will be studied with the Windmill setup. In-source laser spectroscopy will be performed on the entire astatine isotopic chain, using a combination of the Windmill setup, ISOLTRAP MR-ToF and ISOLDE Faraday. Radioactive decay data will be acquired at the Windmill setup throughout those studies and contribute to the global understanding of the phenomenon of shape coexistence in the neutron-deficient lead region.

β-decay properties in the Cs decay chain

Science.gov (United States)

Benzoni, G.; Lică, R.; Borge, M. J. G.; Fraile, L. M.; IDS Collaboration

2018-02-01

The study of the decay of neutron-rich Cs isotopes has two main objectives: on one side β decay is a perfect tool to access the low-spin structures in the daughter Ba nuclei, where the evolution of octupole deformed shapes can be followed, while, on the other hand, the study of the gross properties of these decays, in terms of decay rates and branching to delayed-neutron emission, are fundamental inputs for the modelling of the r-process in the Rare-Earth Elements peak. Results obtained at CERN-ISOLDE are discussed within this framework and compared to existing data and predictions from state-of-the-art nuclear models.

A computer code for calculation of radioactive nuclide generation and depletion, decay heat and γ ray spectrum. FPGS90

International Nuclear Information System (INIS)

Ihara, Hitoshi; Katakura, Jun-ichi; Nakagawa, Tsuneo

1995-11-01

In a nuclear reactor radioactive nuclides are generated and depleted with burning up of nuclear fuel. The radioactive nuclides, emitting γ ray and β ray, play role of radioactive source of decay heat in a reactor and radiation exposure. In safety evaluation of nuclear reactor and nuclear fuel cycle, it is needed to estimate the number of nuclides generated in nuclear fuel under various burn-up condition of many kinds of nuclear fuel used in a nuclear reactor. FPGS90 is a code calculating the number of nuclides, decay heat and spectrum of emitted γ ray from fission products produced in a nuclear fuel under the various kinds of burn-up condition. The nuclear data library used in FPGS90 code is the library 'JNDC Nuclear Data Library of Fission Products - second version -', which is compiled by working group of Japanese Nuclear Data Committee for evaluating decay heat in a reactor. The code has a function of processing a so-called evaluated nuclear data file such as ENDF/B, JENDL, ENSDF and so on. It also has a function of making figures of calculated results. Using FPGS90 code it is possible to do all works from making library, calculating nuclide generation and decay heat through making figures of the calculated results. (author)

A computer code for calculation of radioactive nuclide generation and depletion, decay heat and {gamma} ray spectrum. FPGS90

Energy Technology Data Exchange (ETDEWEB)

Ihara, Hitoshi; Katakura, Jun-ichi; Nakagawa, Tsuneo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1995-11-01

In a nuclear reactor radioactive nuclides are generated and depleted with burning up of nuclear fuel. The radioactive nuclides, emitting {gamma} ray and {beta} ray, play role of radioactive source of decay heat in a reactor and radiation exposure. In safety evaluation of nuclear reactor and nuclear fuel cycle, it is needed to estimate the number of nuclides generated in nuclear fuel under various burn-up condition of many kinds of nuclear fuel used in a nuclear reactor. FPGS90 is a code calculating the number of nuclides, decay heat and spectrum of emitted {gamma} ray from fission products produced in a nuclear fuel under the various kinds of burn-up condition. The nuclear data library used in FPGS90 code is the library `JNDC Nuclear Data Library of Fission Products - second version -`, which is compiled by working group of Japanese Nuclear Data Committee for evaluating decay heat in a reactor. The code has a function of processing a so-called evaluated nuclear data file such as ENDF/B, JENDL, ENSDF and so on. It also has a function of making figures of calculated results. Using FPGS90 code it is possible to do all works from making library, calculating nuclide generation and decay heat through making figures of the calculated results. (author).

HARAD, Decay Isotope Concentration from Atmospheric Noble-Gas Release

International Nuclear Information System (INIS)

Moore, R.E.

1986-01-01

1 - Description of problem or function: HARAD calculates concentrations of radioactive daughters in air following the atmospheric release of a parent radionuclide for a variety of release heights and meteorological conditions. It can be applied most profitably to the assessment of doses to man from the noble gases such as Rn-222, Rn-220, and Xe and Kr isotopes. These gases can produce significant quantities of short-lived particulate daughters in an airborne plume, which are the major contributors to dose. The simultaneous processes of radioactive decay, buildup and environmental loss due to wet and dry deposition on ground surfaces are calculated for a daughter chain in an airborne plume as it is dispersed downwind from a point of release of a parent. 2 - Method of solution: The code evaluates the analytic solution to the set of coupled first order differential equations describing time variation of the concentration of a chain of radionuclides. The analytic solutions assume that the coefficient describing the fractional rate of dry deposition is constant with time. To account for the variation the time coordinate is automatically divided into intervals and a set of average values are used. 3 - Restrictions on the complexity of the problem: - The maximum length of decay chain is 10 nuclides; calculations can be made at a maximum of 24 downwind distances

PKA distributions: Contributions from transmutation products and from radioactive decay

Directory of Open Access Journals (Sweden)

M.R. Gilbert

2016-12-01

Full Text Available The neutrons generated in fusion plasmas interact with materials via nuclear reactions. The resulting transmutations and atomic displacements have life-limiting consequences for fusion reactor components. A detailed understanding of the production, evolution and material consequences of the damage created by cascades of atomic displacements requires, as a vital primary input, a complete description of the energy-spectrum of initial (prompt atomic displacement events (the primary knock on atoms or PKAs produced by direct neutron nuclear interactions. There is also the possibility that the radionuclides produced under transmutation will create further PKAs as they decay, and so the rate of these must also be quantified. This paper presents the latest results from the analysis of PKA spectra under neutron irradiation, focussing particularly on the variation in PKA distributions due to changes in composition under transmutation, but also on the PKA contributions from radioactive decay of materials that become activated under irradiation.

Radioactive decay properties of CANDU fuel. Volume 1: the natural uranium fuel cycle

International Nuclear Information System (INIS)

Clegg, L.J.; Coady, J.R.

1977-01-01

The two books of Volume 1 comprise the first in a three-volume series of compilations on the radioactive decay propertis of CANDU fuel and deal with the natural uranium fuel cycle. Succeeding volumes will deal with fuel cycles based on plutonium recycle and thorium. In Volume 1 which is divided into three parts, the computer code CANIGEN was used to obtain the mass, activity, decay heat and toxicity of CANDU fuel and its component isotopes. Data are also presented on gamma spectra and neutron emissions. Part 3 contains the data relating to the plutonium product and the high level wastes produced during fuel reprocessing. (author)

Nuclear structure and radioactive decay resources at the US National Nuclear Data Center

International Nuclear Information System (INIS)

Sonzogni, A.A.; Burrows, T.W.; Pritychenko, B.; Tuli, J.K.; Winchell, D.F.

2008-01-01

The National Nuclear Data Center has a long tradition of evaluating nuclear structure and decay data as well as offering tools to assist in nuclear science research and applications. With these tools, users can obtain recommended values for nuclear structure and radioactive decay observables as well as links to the relevant articles. The main databases or tools are ENSDF, NSR, NuDat and the new Endf decay data library. The Evaluated Nuclear Structure Data File (ENSDF) stores recommended nuclear structure and decay data for all nuclei. ENSDF deals with properties such as: -) nuclear level energies, spin and parity, half-life and decay modes, -) nuclear radiation energy and intensity for different types, -) nuclear decay modes and their probabilities. The Nuclear Science References (NSR) is a bibliographic database containing nearly 200.000 nuclear sciences articles indexed according to content. About 4000 are added each year covering 80 journals as well as conference proceedings and laboratory reports. NuDat is a software product with 2 main goals, to present nuclear structure and decay information from ENSDF in a user-friendly way and to allow users to execute complex search operations in the wealth of data contained in ENSDF. The recently released Endf-B7.0 contains a decay data sub-library which has been derived from ENSDF. The way all these databases and tools have been offered to the public has undergone a drastic improvement due to advancements in information technology

Multi-day radon signals with a radioactive decay limb-Occurrence and geophysical significance

International Nuclear Information System (INIS)

Steinitz, G.; Martin, M.C.; Gazit-Yaari, N.; Quesada, M.L.; Nuez, J. de la; Casillas, R.; Malik, U.; Begin, Z.B.

2006-01-01

Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geo gas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes

RIBD-IRT, Isotope Buildup and Isotope Decay from Fission Source

International Nuclear Information System (INIS)

1990-01-01

1 - Description of problem or function: RIBD-IRT calculates isotopic concentrations resulting from two fission sources with normal down- chain decay by beta emission and isomeric transfers and inter-chain coupling resulting from (n,gamma) reactions. Calculations can be made to follow an irradiation history through an unlimited number of step changes of unrestricted duration and variability including shutdown periods, restarts at different power levels and/or any other level changes. In addition, the program permits to track and modify the concentration of individual elements as they decay with time following reactor shutdown. Tracking individual elements enables one to estimate time-dependent source terms for a hypothetical LOCA based on known or postulated fission product release mechanisms. 2 - Method of solution: RIBD-IRT is a grid processor. It organizes the various members described by the fission product library data into a grid with the various linkages established from chain branching data, yield data, and neutron capture cross sections with their branching ratios. Radioactive decay includes not only the simple member-to-member cascade but also the more complex forms where branching may be partially or completely skip one or two intervening members

The transfer of radio-active products through food chain

International Nuclear Information System (INIS)

Russell, R.S.

1979-01-01

The food chain mechanism on dry land is considered. The deposition of 90 Sr and 137 Cs are compared and a fuller investigation of 90 Sr deposition on soils. Calculated values of annual mean deposition of 90 Sr, in mCi/Km 2 , and content of milk, in pCi/gCa, from world wide fallout, 1958-75, in the UK agrees well with those observed by within 10%. The significance of radiation doses received through the food chain are discussed. The total estimated average exposure of members of the UK to natural background radiation in 1977 was 1100μSv, of which 0.2% was due to the discharge of radioactive materials into the environment. (U.K.)

Description of new element Z=113 and its α-decay chain

International Nuclear Information System (INIS)

Tai Fei; Chen Dinghan; Xu Chang; Ren Zhongzhou; National Laboratory of Heavy Ion Accelerator, Lanzhou

2005-01-01

RIKEN has produced a new element Z=113 by cold-fusion reaction. Here we systematically study the new nuclide 278 113 and its α-Decay chain using deformed relativistic mean-field theory with three sets of force parameters, TMA, NL-Z2 and NL3. The results are compared with those of the Skyrme-Hartree-Fock model, Moeller et al and also with the new experimental data. The experimental decay energies are well reproduced with RMF. This not only shows the validity of self-consistent field theoretical model in researching the ground state properties of superheavy nuclei, but also shows that prolate deformation is important for the ground state of these nuclei. (authors)

Spin correlations in decay chains involving W bosons TH1"-->

Science.gov (United States)

Smillie, J. M.

2007-08-01

We study the extent to which spin assignments of new particles produced at the LHC can be deduced in the decay of a scalar or fermion C into a new stable (or quasi-stable) particle A through the chain C→B±q, B±→AW±, W±→ℓ±νℓ where ℓ=e,μ. All possible spin assignments of the particles A and B are considered. Explicit invariant mass distributions of the quark and lepton are given for each set of spins, valid for all masses. We also construct the asymmetry between the chains with a W- and those with a W+. The Kullback Leibler distance between the distributions is then calculated to give a quantitative measure of our ability to distinguish the different spin assignments.

New type of natural radioactivity

International Nuclear Information System (INIS)

Rubchenya, V.A.; Chechev, V.P.; Yavshits, S.G.

1987-01-01

Consideration is being given in popular form to investigations of a new type of natural radioactivity - spontaneous emission of fragments, more massive than α-particles, by heavy element nuclei, called f-decay by analogy with known α and γ decays. Some data on radioactivity, origin of the decay are presented. Possibilities of f-decay, predictions and hypotheses are discussed. The reason of late discovery of f-decay lies in low f-decay probability 10 -9 with respect to α-decay and in a certain sluggishness of settled knowledge about possible types of radioactive decay. The idea of f-decay is presented. It differs from the idea about a new type of decay as modification of asymmetric fission and contains an attempt to explain the intermediate position of f-decay between α-decay and

MODESTY, Statistical Reaction Cross-Sections and Particle Spectra in Decay Chain

International Nuclear Information System (INIS)

Mattes, W.

1977-01-01

1 - Nature of the physical problem solved: Code MODESTY calculates all energetically possible reaction cross sections and particle spectra within a nuclear decay chain. 2 - Method of solution: It is based on the statistical nuclear model following the method of Uhl (reference 1) where the optical model is used in the calculation of partial widths and the Blatt-Weisskopf single particle model for gamma rays

Laser enhanced radioactive decay and selective transmutation of nuclear waste

International Nuclear Information System (INIS)

Saloman, R.; Aarnio, P.; Ala-Heikkila, J.; Hakola, A.; Santala, M.

2007-01-01

We have investigated narrow-band coherent laser radiation - ranging from visible to X- and to gamma-ray wave length region - and their interactions both directly with photon-nuclear couplings and indirectly through the photon-electron and electron-nucleus interactions. In particular we discuss various means of selective excitation of nuclear resonance states by narrowband lasers. During the relaxation process the active nucleus may return to its initial ground-state or find another final state. In the latter case the nucleus is transmuted into a state which may have beneficial properties for instance concerning radioactivity. One ideal case would be the destruction of long-lived nuclear waste isotopes into faster decaying ones. The essential presumption is that the excitation process is selective and efficient as regards background processes due to unwanted excitation channels of the primary isotope and due to other surrounding nuclides. The paper consists of 1) a short review of generating short-wave length coherent light sources, 2) a survey of potential photon-induced nuclear states and their decay channels, and 3) a determination of the selectivity of the transmutation process

Transport of a Two-Member Decay Chain of Radionuclides Through a Discrete Fracture in a Porous Rock Matrix in the Presence of Colloids

International Nuclear Information System (INIS)

Tien, N.-C.; Li Shihhai

2002-01-01

Many physical and chemical processes dominate the transport of radionuclides in groundwater. Among these processes, the decay chain process of radionuclides was frequently disregarded in previous research. However, the daughter products may travel much farther than their parents along the fracture. Therefore, some models neglecting the effect of the decay chain may underestimate the transport radionuclide concentration in geological media. The transport of radionuclides in groundwater is also controlled by colloidal particles. The radionuclides may be enhanced or retarded by the colloids, according to the mobility of these colloidal particles. This work describes a novel model of the transport of a two-member decay chain of radionuclides through a discrete fracture in a porous rock matrix in the presence of colloids. The model addresses the following processes: (a) advective transport in the fracture, (b) mechanical dispersion and molecular diffusion along the fracture, (c) molecular diffusion from the fracture to the rock matrix, (d) adsorption onto the fracture wall, (e) adsorption in the rock matrix, and (f) radioactive decay. Furthermore, colloids are assumed to be excluded from the matrix pores because of their size. A fully developed concentration profile system with nonreactive colloids is used to understand the effect of colloidal sizes by using hydrodynamic chromatography. The external forces acting on the colloid surface, such as the inertial, the van der Waals attractive force, the double layer force, and the gravitational force are accounted for. The parameters, the average velocity of the colloid, the dispersion coefficient of the colloid, and the distribution coefficient of radionuclides with colloids are modified according to the colloidal size. The transport equations for the parent radionuclides are solved analytically using the Laplace transformation and inversion method. However, for the transformed solution of the daughter products along the

An analytical model for radioactive pollutant release simulation in the atmospheric boundary layer

International Nuclear Information System (INIS)

Weymar, Guilherme J.; Vilhena, Marco T.; Bodmann, Bardo E.J.; Buske, Daniela; Quadros, Regis

2013-01-01

Simulations of emission of radioactive substances in the atmosphere from the Brazilian nuclear power plant Angra 1 are a necessary tool for control and elaboration of emergency plans as a preventive action for possible accidents. In the present work we present an analytical solution for radioactive pollutant dispersion in the atmosphere, solving the time-dependent three-dimensional advection-diffusion equation. The experiment here used as a reference in the simulations consisted of the controlled releases of radioactive tritiated water vapor from the meteorological tower close to the power plant at Itaorna Beach. The wind profile was determined using experimental meteorological data and the micrometeorological parameters were calculated from empirical equations obtained in the literature. We report on a novel analytical formulation for the concentration of products of a radioactive chain released in the atmospheric boundary layer and solve the set of coupled equations for each chain radionuclide by the GILTT solution, assuming the decay of all progenitors radionuclide for each equation as source term. Further we report on numerical simulations, as an explicit but fictitious example and consider three radionuclides in the radioactive chain of Uranium 235. (author)

An analytical model for radioactive pollutant release simulation in the atmospheric boundary layer

Energy Technology Data Exchange (ETDEWEB)

Weymar, Guilherme J.; Vilhena, Marco T.; Bodmann, Bardo E.J., E-mail: guicefetrs@gmail.com, E-mail: mtmbvilhena@gmail.com, E-mail: bejbodmann@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Buske, Daniela; Quadros, Regis, E-mail: danielabuske@gmail.com, E-mail: quadros99@gmail.com [Universidade Federal de Pelotas (UFPel), Capao do Leao, RS (Brazil). Programa de Pos-Graduacao em Modelagem Matematica

2013-07-01

Simulations of emission of radioactive substances in the atmosphere from the Brazilian nuclear power plant Angra 1 are a necessary tool for control and elaboration of emergency plans as a preventive action for possible accidents. In the present work we present an analytical solution for radioactive pollutant dispersion in the atmosphere, solving the time-dependent three-dimensional advection-diffusion equation. The experiment here used as a reference in the simulations consisted of the controlled releases of radioactive tritiated water vapor from the meteorological tower close to the power plant at Itaorna Beach. The wind profile was determined using experimental meteorological data and the micrometeorological parameters were calculated from empirical equations obtained in the literature. We report on a novel analytical formulation for the concentration of products of a radioactive chain released in the atmospheric boundary layer and solve the set of coupled equations for each chain radionuclide by the GILTT solution, assuming the decay of all progenitors radionuclide for each equation as source term. Further we report on numerical simulations, as an explicit but fictitious example and consider three radionuclides in the radioactive chain of Uranium 235. (author)

Cold valleys in the radioactive decay of 248-254Cf isotopes

International Nuclear Information System (INIS)

Biju, R.K.; Sahadevan, Sabina; Santhosh, K.P.; Joseph, Antony

2008-01-01

Based on the concept of cold valley in cold fission and fusion, we have investigated the cluster decay process in 248-254 Cf isotopes. In addition to alpha particle minima, other deep minima occur for S, Ar and Ca clusters. It is found that inclusion of proximity potential does not change the position of minima but minima become deeper. Taking Coulomb and proximity potential as interacting barrier for post-scission region, we computed half-lives and other characteristics for various clusters from these parents. Our study reveals that these parents are stable against light clusters and unstable against heavy clusters. Computed half-lives for alpha decay agree with experimental values within two orders of magnitude. The most probable clusters from these parents are predicted to be 46 Ar, 48,50 Ca which indicate the role of doubly or near doubly magic clusters in cluster radioactivity. Odd A clusters are found to be favorable for emission from odd A parents. Cluster decay model is extended to symmetric region and it is found that symmetric fission is also probable which stresses the role of doubly or near doubly magic 132 Sn nuclei. Geiger-Nuttal plots were studied for various clusters and are found to be linear with varying slopes and intercepts. (author)

In sæcula sæculorum: A lab activity to create with students a radioactive secular equilibrium model⋆

Science.gov (United States)

Santostasi, D.

2017-03-01

The teaching of radioactivity in the high school is often difficult to implement, especially from an experimental point of view. In this paper an activity based on a laboratory experiment on radioactivity is presented. The activity was proposed to high school students in their fourth year of studies attending the summer internship organized by the University of Pavia at the Department of Physics. The experiement concerns the radon decay chain, and in particular the measurement of the activity of 214Bi , both in absence and in presence of its progenitor 222Rn . This way it is possible to observe two different decay curves: the first provides a 214Bi decay constant in agreement with the theoretical one, whereas the trend of the second one can be understood only through the hypothesis of secular equilibrium with 222Rn . Using an engaging and interesting game with dice, a model of radioactive decay was developed and performed with students divided in small groups.

Alloy development for fast induced radioactivity decay for fusion reactor applications

International Nuclear Information System (INIS)

Klueh, R.L.; Bloom, E.E.

1984-03-01

The Cr-Mo ferritic (martensitic) steels and austenitic stainless steels (primarily type 316 and variations on that composition) are the leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment produces long-lived radioactive isotopes. These isotopes lead to difficult radioactive waste disposal problems once the structure is removed from service. Such problems could be reduced by developing steels that contain only elements that produce radioactive isotopes that decay to low levels in a reasonable time (tens of years instead of hundreds or thousands of years). This report discusses the development of such steels by making elemental substitutions in the steels now under consideration. Molybdenum must be replaced in the Cr-Mo steels; nickel and molybdenum both must be replaced in the austenitic stainless steels (the nitrogen concentration must be limited, and niobium, maintained to extremely low levels). Appropriate substitutions are tungsten for molybdenum in the Cr-Mo steels and manganese for nickel in the austenitic stainless steels. Indications are that suitable ferritic steels can be developed, but development of a nickel-free austenitic stainless steel with properties similar to the Cr-Ni stainless steels appears to be much more complex

Evaluation of maximum radionuclide concentration from decay chains migration in aquifers

International Nuclear Information System (INIS)

Aquino Branco, O.E. de.

1983-01-01

The mathematical formulation of the mechanisms involved in the transport of contaminants in aquifers is presented. The methodology employed is described. A method of calculation the maximum concentration of radionuclides migrating in the underground water, and resulting from one decay chain, is then proposed. As an example, the methodology is applied to a waste basin, built to receive effluents from a hypothectical uranium ore mining and milling facility. (M.A.C.) [pt

Spectroscopic Tools Applied to Element Z = 115 Decay Chains

Directory of Open Access Journals (Sweden)

Forsberg U.

2014-03-01

Full Text Available Nuclides that are considered to be isotopes of element Z = 115 were produced in the reaction 48Ca + 243Am at the GSI Helmholtzzentrum für Schwerionenforschung Darmstadt. The detector setup TASISpec was used. It was mounted behind the gas-filled separator TASCA. Thirty correlated α-decay chains were found, and the energies of the particles were determined with high precision. Two important spectroscopic aspects of the offline data analysis are discussed in detail: the handling of digitized preamplified signals from the silicon strip detectors, and the energy reconstruction of particles escaping to upstream detectors relying on pixel-by-pixel dead-layer thicknesses.

Nuclear decay data for radionuclides occurring in routine releases from nuclear fuel cycle facilities

Energy Technology Data Exchange (ETDEWEB)

Kocher, D.C.

1977-08-01

This report gives tabulations of the atomic and nuclear radiations emitted by 240 radionuclides. Most of the radionuclides are those expected to occur in routine releases of effluents from nuclear fuel cycle facilities. For each radionuclide are given the half-life and recommended values for the energies, intensities, and equilibrium absorbed-dose constants for each of the atomic and nuclear radiations. Also given are the daughter radionuclides produced and recommended values for decay branching ratios, where applicable. The radioactivity decay chains and branching ratios are displayed in diagram form.

Nuclear decay data for radionuclides occurring in routine releases from nuclear fuel cycle facilities

International Nuclear Information System (INIS)

Kocher, D.C.

1977-08-01

This report gives tabulations of the atomic and nuclear radiations emitted by 240 radionuclides. Most of the radionuclides are those expected to occur in routine releases of effluents from nuclear fuel cycle facilities. For each radionuclide are given the half-life and recommended values for the energies, intensities, and equilibrium absorbed-dose constants for each of the atomic and nuclear radiations. Also given are the daughter radionuclides produced and recommended values for decay branching ratios, where applicable. The radioactivity decay chains and branching ratios are displayed in diagram form

Test what you eat. Monitoring of radioactivity in the food chain

International Nuclear Information System (INIS)

2014-01-01

Since 2013, the total beta activity in animal feed products being exported to Belarus shall be lower than 600 Becquerel per kilogram. The Belgian Nuclear Research Center SCK-CEN carries out these checks on behalf of the professional association of compound feed manufacturers in Belgium. The article discusses work conducted by SCK-CEN relating to the monitoring of radioactivity in the food chain.

α decay and cluster radioactivity of nuclei of interest to the synthesis of Z =119 , 120 isotopes

Science.gov (United States)

Poenaru, D. N.; Gherghescu, R. A.

2018-04-01

Super-heavy nuclei of interest for the forthcoming synthesis of the isotopes with Z =119 , 120 are investigated. One of the very interesting latest experiments was performed at the velocity filter SHIP (GSI Darmstadt) trying to produce 299120 in a fusion reaction 248Cm(54Cr,3 n )299120 . We report calculations of α -decay half-lives using four models: AKRA (Akrawy), ASAF (analytical superasymmetric fission), UNIV (universal formula), and semFIS (semi-empirical formula based on fission theory). The released energy, Q , is calculated using the theoretical model of atomic masses, WS4. For Sr,9492 cluster radioactivity of 120,302300 we predict a branching ratio relative to α decay of -0.10 and 0.49, respectively, meaning that it is worth trying to detect such kinds of decay modes in competition with α decay.

The Effect of Herbal Mouthwashes on the Force Decay of Elastomeric Chains: An In-vitro Study

Directory of Open Access Journals (Sweden)

Mohammed Nahidh

2017-10-01

Full Text Available Background: This in vitro study aimed to evaluate the effect of four herbal mouthwashes on the force decay of two types of clear short elastomeric chains (Regular and Extreme at various time intervals. Materials and methods: Four hundred forty pieces of both types of elastomeric chains with 19 mm length were utilized in this study. The force was measured, using digital scale immediately, after one-day immersion in distilled water and after 1, 2, 3 and 4 weeks immersion in the specific mouthwash for one minute twice daily then washed and kept in distilled water at 37°C. Force decay was calculated and compared among different elastic types, mouthwashes and time intervals using t-test and one-way ANOVA then Tukey’s tests. Results: The force degradation of regular type was significantly higher than extreme one. With time, the force decay increased significantly in both types. There was non-significant difference among the mouthwashes in the first and second weeks while the opposite in the third and fourth especially with the control group. Conclusions: The extreme type is preferred over the regular one because of its low force decay and the tested mouthwashes have no clinical significant effect on the force degradation over time in comparison with distilled water.

Updated model for radionuclide transport in the near-surface till at Forsmark - Implementation of decay chains and sensitivity analyses

International Nuclear Information System (INIS)

Pique, Angels; Pekala, Marek; Molinero, Jorge; Duro, Lara; Trinchero, Paolo; Vries, Luis Manuel de

2013-02-01

overestimate radionuclide concentrations at the discharge zone). Specifically, examination of the modelling results indicates that: 1. The implementation of the revised till stratigraphy has an overall small impact on the modelling results: despite distinctly different groundwater flow patterns, tracer arrival at the discharge zone is similar between the previous and current till models. 2. Of the radionuclides studied only 226 Ra is significantly affected by radioactive chain decay dynamics. 3. The values of geochemical parameters used in the Base Case reactive transport calculations produce conservative results. 4. The model is largely insensitive to significant variations in dispersivity of the till and an alternative definition of the shallow groundwater inflow, although the elimination of vertical stratification in hydraulic conductivity has the effect to speed up radionuclide transport. 5. Over saturation with barite is not reached under any of the considered scenarios hence Ra coprecipitation with barite does not contribute to 226 Ra retardation under the assumptions of the model. In contrast, Sr co-precipitation with calcite is an important retention mechanism for 90 Sr

New experimental data on the influence of extranuclear factors on the probability of radioactive decay

CERN Document Server

Bondarevskij, S I; Skorobogatov, G A

2002-01-01

New experimental data on influence of various extranuclear factors on probability (lambda) of radioactive decay are presented. During redox processes in solutions containing sup 1 sup 3 sup 9 Ce relative change in lambda measured by the DELTA I/I method was [I(Ce sup I sup V)-I(Ce sup I sup I sup I)]/I sub m sub e sub a sub n +(1.4+-0.6)x10 sup - sup 4. Using a modification of the method based on displacement of the age-old radioactive equilibrium, when a source MgO( sup 1 sup 2 sup 1 sup m Te) was cooled to 78 K, growth of lambda of tellurium nuclear isomer by 0.04+-0.02% was detected. New experimental data on increase in gamma-radioactivity of sample Be sup 1 sup 2 sup 3 sup m Te at the expense of low-temperature induced reaction, i.e. collective nuclear superluminescence, are provided

Key radionuclides and parameters that determine performance of geologic repositories for high-level radioactive wastes

International Nuclear Information System (INIS)

Joonhong Ahn; Atsuyuki Suzuki

1993-01-01

This paper presents results of a mathematical analysis for performance of the engineered barriers of high-level radioactive waste repositories. The main body of the mathematical model developed in this study is mass transport of actinides in a bentonite region. In an analysis of actinide transport, radioactive decay chain and effects of low solubilities must be taken into account. In many previous models for mass transport in engineered barriers including radioactive decay chain, however, boundary conditions at the interface between the waste form and the bentonite region cannot be determined flexibly. In some models, solubility-limited boundary condition is assumed for all the members in a chain. In order to investigate what are key radionuclides and parameters that control performance of engineered barriers of a geologic repository, we must evaluate mass transport with the source boundary condition determined by a detailed analysis on mass transfer at the boundary. In this study, we developed a mathematical model, which can determine whether the inner boundary condition is solubility-limited or congruent release, based on a mathematical analysis for mass transfer at the glass dissolution location, and how long the solubility-limited boundary condition applies. Based on the mathematical model, we point out radionuclides and parameters that have primary influences on the performance of a repository, and investigate a reasonable strategy for coupling geologic disposal and partitioning of those key radionuclides from the standpoint of reducing hazard of geologic disposal. (authors). 4 tabs., 2 figs., 8 refs

Chemical effects of the radioactive decay 7677Kr→7677Br reactions of recoil bromine in the gas phase

International Nuclear Information System (INIS)

Jong, D. de.

1982-01-01

This thesis describes the chemical reactions of 76 Br and 77 Br recoil species, formed by radioactive decay of 76 Kr and 77 Kr, with various gaseous compounds. Due to differences in decay energy and decay mode the resulting 76 Br and 77 Br isotopes obtain different kinetic energies and carry different charges; 76 Kr decays completely via electron capture and the resulting 76 Br is formed with a multiple positive charge and a kinetic energy of 7.2 eV at the most. 77 Kr decays for only 16% via electron capture, resulting in 77 Brsup(n+) ions with a maximal kinetic energy of 56.9 eV. 84% of the 77 Kr decays via #betta# + particle emission, which leads to 77 Br species, that are mainly negative or uncharged and that possess a maximal kinetic energy of 36.4 eV. The aim of this study was to explore whether these initial differences in charge and kinetic energy are reflected in the products, formed after chemical reactions of 76 Br and 77 Br. (Auth.)

Development of a computational algorithm for the linearization of decay and transmutation chains

International Nuclear Information System (INIS)

Cruz L, C. A.; Francois L, J. L.

2017-09-01

One of the most used methodologies to solve Bate man equations, in the problem of burning, is the Tta (Transmutation Trajectory Analysis) method. In this method, a network of decays is broken down into linear elements known as trajectories, through a process known as linearization. In this work an alternative algorithm is shown to find and construct these trajectories, which considers three aspects of linearization: the information -a priori- about the elements that make up decay and transmutation network, the use of a new notation, and in the functions for the treatment of text strings (which are common in most programming languages). One of the main advantages of the algorithm is that can condense the information of a decay and transmutation network into only two vectors. From these is possible to determine how many linear chains can be extracted from the network and even their length (in the case they are not cyclical). Unlike the Deep First Search method, which is widely used for the linearization process, the method proposed in the present work does not have a backward routine and instead occupies a process of compilation, since completes fragments chain instead of going back to the beginning of the trajectories. The developed algorithm can be applied in a general way to the information search and to the linearization of the computational data structures known as trees. It can also be applied to engineering problems where one seeks to calculate the concentration of some substance as a function of time, starting from linear differential equations of balance. (Author)

Discovery of the radioactive decay of 223Ra by 14C emission and experiments with the magnetic spectrometer Soleno

International Nuclear Information System (INIS)

Hourani, E.; Hussonnois, M.

1987-01-01

The aim of this report is to review the experiment of Rose and Jones (discovery in 1984 of radioactive decay of 223 Ra by 14 C nuclei emission) with the subsequent one of Alexandrov (et al) performed with the same technique. The experiments performed by the group at Orsay on 14 C radioactivity of radium isotopes with the magnetic spectrometer Soleno are also reviewed. This review comprises the presentation and comments of the original results and arguments taken in their historical context

Nuclide transport of decay chain in the fractured rock medium: a model using continuous time Markov process

International Nuclear Information System (INIS)

Younmyoung Lee; Kunjai Lee

1995-01-01

A model using continuous time Markov process for nuclide transport of decay chain of arbitrary length in the fractured rock medium has been developed. Considering the fracture in the rock matrix as a finite number of compartments, the transition probability for nuclide from the transition intensity between and out of the compartments is represented utilizing Chapman-Kolmogorov equation, with which the expectation and the variance of nuclide distribution for the fractured rock medium could be obtained. A comparison between continuous time Markov process model and available analytical solutions for the nuclide transport of three decay chains without rock matrix diffusion has been made showing comparatively good agreement. Fittings with experimental breakthrough curves obtained with nonsorbing materials such as NaLS and uranine in the artificial fractured rock are also made. (author)

The Synthesis and Decay Properties of the Heaviest Elements

CERN Document Server

Oganessian, Yu T

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the "islands of stability" of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus ^{208}Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with ^{48}Ca. In these reactions the decay chains of heavy atoms consisting of sequential alpha-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first exper...

Some critical remarks on a sequence of events interpreted to possibly originate from a decay chain of an element 120 isotope

Energy Technology Data Exchange (ETDEWEB)

Hessberger, F.P. [GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Helmholtz-Institut Mainz, Mainz (Germany); Ackermann, D. [GANIL, Caen (France)

2017-06-15

A sequence of three events observed in an irradiation of {sup 248}Cm with {sup 54}Cr at the velocity filter SHIP of the GSI - Helmholtzzentrum fuer Schwerionenforschung GmbH, 64291 Darmstadt, Germany, had been interpreted as a decay chain consisting of three α particles. On the basis of measured energies, a possible assignment to the decay of an isotope of element 120 was discussed, although it was stated that a definite assignment could not be made. A critical analysis of the data, however, shows that the reported events do not have the properties of a decay chain consisting of three α particles and (probably being terminated by) a spontaneous fission event, but that this is rather a random sequence of events. (orig.)

Decay schemes of the radioactive nuclei A = 225 to 229. Skhemy raspada radioaktivnykh yader A = 225 - 229

Energy Technology Data Exchange (ETDEWEB)

Dzhelepov, B S; Ivanov, R B; Mikhailova, M A

1976-01-01

This monograph is devoted to properties of atomic nuclei with mass numbers A = 225 to 229. The book collects and systematizes all of the experimental data characterizing properties of radioactive isotopes: information concerning masses of nuclei, magnetic and electric moments, lifetimes of nuclear states, the most reliable information on characteristics of radiations, quantum characteristics of levels and other properties of the studied nuclei. On basis of a critical analysis of the totality of information, decay schemes of radioactive nuclei with mass numbers A = 225 to 229 were constructed, as well as the series of excited states of the isotopes which lie in this region of nuclei.

Map of calculated radioactivity of fission product, (4)

International Nuclear Information System (INIS)

Takeda, Tsuneo

1978-07-01

The overall radioactivities of fission products depending on irradiation time and cooling time were calculated for 18 different neutron fluxes, which are presented in contour maps and tables. Irradiation condition etc. are the followings: neutron flux (n sub(th)) 1 x 10 12 - 6.8 x 10 14 n/cm 2 /sec, uranium quantity 1 mole (6 x 10 23 atoms, ca. 271 g UO 2 ), U-235 enrichment 2.7%, irradiation time 60. - 6 x 10 7 sec (1 min - 1.9 y), cooling time 0. and 60. - 6 x 10 7 sec (1 min - 1.9 y). The enrichment value represents those for LWRs. To calculate the overall radioactivities, 595 fission product nuclides were introduced. Overall radioactivities calculations were made for 68,000 combinations of irradiation time, cooling time and neutron flux. The many complex decay chains of fission products were treated with CODAC-No.6 computer code. (author)

Determination of radioactivity in Chinese phosphate rock and fertilizer

International Nuclear Information System (INIS)

Chen Jingjian; Zhu Yongyi; Yang Juncheng

1993-01-01

The presented paper reported the radioactivity of U-238, Ra-226, Th-232 and K-40 in Chinese phosphate rocks by gamma spectrographic analysis during 1985-1990. The results showed that the decay chain of U-238-Ra-226 was the main source of radionuclides in phosphate rocks. The radionuclides in phosphate fertilizer differed from the forms of phosphate fertilizer. U-238 was the most important radionuclide in phosphoric compound fertilizer. The transfer rate of radionuclides was also estimated. (2 figs., 1 tab.)

Experimental study of precisely selected evaporation chains in the decay of excited 25Mg

Science.gov (United States)

Camaiani, A.; Casini, G.; Morelli, L.; Barlini, S.; Piantelli, S.; Baiocco, G.; Bini, M.; Bruno, M.; Buccola, A.; Cinausero, M.; Cicerchia, M.; D'Agostino, M.; Degelier, M.; Fabris, D.; Frosin, C.; Gramegna, F.; Gulminelli, F.; Mantovani, G.; Marchi, T.; Olmi, A.; Ottanelli, P.; Pasquali, G.; Pastore, G.; Valdré, S.; Verde, G.

2018-04-01

The reaction 12C+13C at 95 MeV bombarding energy is studied using the Garfield + Ring Counter apparatus located at the INFN Laboratori Nazionali di Legnaro. In this paper we want to investigate the de-excitation of 25Mg aiming both at a new stringent test of the statistical description of nuclear decay and a direct comparison with the decay of the system 24Mg formed through 12C+12C reactions previously studied. Thanks to the large acceptance of the detector and to its good fragment identification capabilities, we could apply stringent selections on fusion-evaporation events, requiring their completeness in charge. The main decay features of the evaporation residues and of the emitted light particles are overall well described by a pure statistical model; however, as for the case of the previously studied 24Mg, we observed some deviations in the branching ratios, in particular for those chains involving only the evaporation of α particles. From this point of view the behavior of the 24Mg and 25Mg decay cases appear to be rather similar. An attempt to obtain a full mass balance even without neutron detection is also discussed.

Cluster decay of 218U isotope

International Nuclear Information System (INIS)

Shivakumaraswamy, G.; Umesh, T.K.

2012-01-01

The phenomenon of spontaneous emission of charged particles heavier than alpha particle and lighter than a fission fragment from radioactive nuclei without accompanied by the emission of neutrons is known as cluster radioactivity or exotic radioactivity. The process of emission of charged particles heavier than alpha particle and lighter than a fission fragment is called exotic decay or cluster decay. The phenomenon of cluster radioactivity was first predicted theoretically by Sandulescu et al in 1980. Rose and Jones made first experimental observations of 14 C emission from 223 Ra in 1984. Several cluster decay modes in trans-lead region have been experimentally observed. The half-life values for different modes of cluster decay from different isotopes of uranium have been calculated using different theoretical models such as the analytical super asymmetric model (ASAFM), Preformed cluster model (PCM) and Coulomb and Proximity potential model (CPPM) etc. Recently some semi-empirical formulae, i.e, single line of universal curve (UNIV), Universal decay law (UDL) for both alpha and cluster radioactivity have also been proposed to explain cluster decay data. The alpha decay half-life of 218-219 U isotopes has been experimentally measured in 2007. The half-life values for different cluster decay modes of 218 U isotopes have been calculated PCM model. Recently in 2011, the half-life values have also been calculated for some cluster decay modes of 222-236 U isotopes using the effective liquid drop description with the varying mass asymmetry (VMAS) shape and effective inertial coefficient. In the light of this, in the present work we have studied the cluster radioactivity of 218 U isotope. The logarithmic half-lives for few cluster decay modes from 218 U isotope have been calculated by using three different approaches, i.e, UNIV proposed by Poenaru et al in 2011, UDL proposed by Qi et al in 2009 and the CPPM model proposed by Santhosh et al in 2002. The CPPM based

Updated model for radionuclide transport in the near-surface till at Forsmark - Implementation of decay chains and sensitivity analyses

Energy Technology Data Exchange (ETDEWEB)

Pique, Angels; Pekala, Marek; Molinero, Jorge; Duro, Lara; Trinchero, Paolo; Vries, Luis Manuel de [Amphos 21 Consulting S.L., Barcelona (Spain)

2013-02-15

tendency to overestimate radionuclide concentrations at the discharge zone). Specifically, examination of the modelling results indicates that: 1. The implementation of the revised till stratigraphy has an overall small impact on the modelling results: despite distinctly different groundwater flow patterns, tracer arrival at the discharge zone is similar between the previous and current till models. 2. Of the radionuclides studied only {sup 226}Ra is significantly affected by radioactive chain decay dynamics. 3. The values of geochemical parameters used in the Base Case reactive transport calculations produce conservative results. 4. The model is largely insensitive to significant variations in dispersivity of the till and an alternative definition of the shallow groundwater inflow, although the elimination of vertical stratification in hydraulic conductivity has the effect to speed up radionuclide transport. 5. Over saturation with barite is not reached under any of the considered scenarios hence Ra coprecipitation with barite does not contribute to {sup 226}Ra retardation under the assumptions of the model. In contrast, Sr co-precipitation with calcite is an important retention mechanism for {sup 90}Sr.

Migration of radionuclide chains through an adsorbing medium

International Nuclear Information System (INIS)

Lester, D.H.; Jansen, G.; Burkholder, H.C.

1974-12-01

The migration of actinides and other radionuclides from an underground geologic nuclear waste disposal site through a soil column to a surface water body was investigated for impulse and band releases. Numerical calculation of the analytical solutions revealed that differences in adsorption characteristics between chain members, axial dispersion, and radioactive decay all act to reduce radionuclide discharge rates at the exit of the soil column. The results of the study may have important implications in the underground storage and disposal of nuclear waste. (U.S.)

The monitoring of radioactive substances in biological food chains by the veterinary service in Czechoslovakia

Energy Technology Data Exchange (ETDEWEB)

Pawel, O [Central State Veterinary Institute, Prague, Czechoslovakia (Czech Republic)

1986-07-01

Czechoslovakia has established an environmental monitoring system to protect the hygienic conditions of the environment from the radiation hazard. The control authorities of the Ministry of Agriculture and Food take part in this system in order to collect information on the contamination with radioactive substances of soil, plants, game, food animals, foodstuffs and raw materials, i.e. information on all links of the food chain which extends from animals to man. A radioactive substances detection programme has been launched by the appropriate authorities in agriculture, animal husbandry and veterinary service. The programme includes a two-stage laboratory analysis of radioactive substances. The majority of laboratories covering the programme are already in operation.

The monitoring of radioactive substances in biological food chains by the veterinary service in Czechoslovakia

International Nuclear Information System (INIS)

Pawel, O.

1986-01-01

Czechoslovakia has established an environmental monitoring system to protect the hygienic conditions of the environment from the radiation hazard. The control authorities of the Ministry of Agriculture and Food take part in this system in order to collect information on the contamination with radioactive substances of soil, plants, game, food animals, foodstuffs and raw materials, i.e. information on all links of the food chain which extends from animals to man. A radioactive substances detection programme has been launched by the appropriate authorities in agriculture, animal husbandry and veterinary service. The programme includes a two-stage laboratory analysis of radioactive substances. The majority of laboratories covering the programme are already in operation

Distinguishing spins in decay chains with photons at the large hardron collider

Energy Technology Data Exchange (ETDEWEB)

Ehrenfeld, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Freitas, A. [Department of Physics and Astronomy, Univ. of Pittsburgh, PA (United States); Landwehr, A.; Wyler, D. [Institut fuer Theoretische Physik, Univ. Zuerich (Switzerland)

2009-04-15

Several models for physics beyond the Standard Model predict new particles with a decay signature including hard photons and missing energy. Two well-motivated examples are supersymmetry with gauge-mediated breaking (GMSB) and the standard model with two universal extra dimensions. Both models lead to decay chains with similar collider signatures, including hard photon emission. The main discriminating feature are the spins of the new particles. In this paper we discuss how information about the spins of the particles can be extracted from lepton-photon or quark-photon invariant mass distributions at the Large Hadron Collider. The characteristic shapes of the distributions are derived analytically and then studied in a realistic Monte-Carlo simulation. We find that for a typical GMSB mass spectrum with particle masses below 1 TeV, already 10 fb{sup -1} integrated luminosity at 14 TeV center-of-mass energy are sufficient to discriminate the two models with high significance. (orig.)

Distinguishing spins in decay chains with photons at the large hardron collider

International Nuclear Information System (INIS)

Ehrenfeld, Wolfgang; Freitas, A.; Landwehr, A.; Wyler, D.

2009-04-01

Several models for physics beyond the Standard Model predict new particles with a decay signature including hard photons and missing energy. Two well-motivated examples are supersymmetry with gauge-mediated breaking (GMSB) and the standard model with two universal extra dimensions. Both models lead to decay chains with similar collider signatures, including hard photon emission. The main discriminating feature are the spins of the new particles. In this paper we discuss how information about the spins of the particles can be extracted from lepton-photon or quark-photon invariant mass distributions at the Large Hadron Collider. The characteristic shapes of the distributions are derived analytically and then studied in a realistic Monte-Carlo simulation. We find that for a typical GMSB mass spectrum with particle masses below 1 TeV, already 10 fb -1 integrated luminosity at 14 TeV center-of-mass energy are sufficient to discriminate the two models with high significance. (orig.)

Structure effects in the region of superheavy elements via the alpha-decay chain of sup 2 sup 9 sup 3 118

CERN Document Server

Gupta, R K; Kumar, R; Balasubramaniam, M; Scheid, W

2002-01-01

The alpha-decay chain of sup 2 sup 9 sup 3 118, first proposed in the Berkeley cold fusion experiment sup 2 sup 0 sup 8 Pb( sup 8 sup 6 Kr, 1n) and now retracted, is calculated by using the preformed cluster model (PCM) of one of the authors (RKG). Also, the possible branchings of alpha-decays to heavier cluster decays of all the parents in this chain are calculated for the first time. The calculated Q-values, penetrabilities and preformation factors for alpha-decays suggest that the sup 2 sup 8 sup 5 114 nucleus with Z=114, N=171 is a magic nucleus, either due to the magicity of Z=114, or N=172 or both. The N=172 is proposed to be a magic number in certain relativistic mean-field calculations, but with Z 120. The calculated cluster decays point to new interesting possibilities of sup 1 sup 4 C decay of the sup 2 sup 8 sup 1 112 parent, giving rise to a (reasonably) deformed Z=106, N=161, sup 2 sup 6 sup 7 106 daughter (N=162 being now established as the deformed magic shell) or to a doubly magic sup 4 sup 8 ...

Radioactivity in marine food chains

International Nuclear Information System (INIS)

Renfro, W.C.

1973-01-01

A few years ago the writer of a popular article on radioactivity in the oceans suggested that future historians will record that man began to reap the benefits of nuclear energy and the oceans almost simultaneously. Indeed, nuclear power may prove to be a major factor in the exploration, study, and rational use of the oceanic areas covering more than two-thirds of the earth. Most uses of nuclear energy result in the production of some unwanted radioactive wastes. Naturally, high-level wastes are very carefully controlled and stored; and low-level radioactive wastes and by-products are only permitted to enter the environment under the strictest precautions. Research on the fates of radioisotopes entering the marine environment is the province of marine radio-ecologists. This article will touch on some studies of radioecologists concerning the transfer of radioactive materials between water, plants, animals, and sediments in the oceans. (author)

Search for right-handed currents in the decay chain of K+ → μ+νμ, μ+ → e+νeν-barμ

International Nuclear Information System (INIS)

Aoki, M.; Yamazaki, T.; Imazato, J.

1993-12-01

The asymmetry of positrons in the K + → μ + ν, μ + → e + ν e ν-bar μ decay chain was measured in a search for right-handed weak currents in ΔS = 1 semi-leptonic decay. High-intensity low-background monoenergetic polarized muons of 236 MeV/c momentum resulting from kaon decay at rest were directly extracted from a primary production target which was hit by a proton beam of the KEK 12-GeV proton synchrotron. Muons were stopped in a pure-aluminum plate, and the energy-integrated asymmetry of the decay positrons with respect to the incoming muon direction was determined to high precision. The observed asymmetry yielded ξP μ = -0.9996 ± 0.0030(stat) ± 0.0048(sys). This result revealed no evidence of right-handed currents in this kaon-decay chain, and set a stringent bound on the mass of the right-handed weak boson. (author) 52 refs

RETADD-II: a long-range atmospheric trajectory model with consistent treatment of deposition loss and species growth and decay

International Nuclear Information System (INIS)

Murphy, B.D.; Ohr, S.Y.; Begovich, C.L.

1984-08-01

A versatile model is described which estimates long-range atmospheric dispersion based on plume trajectories. This model allows the treatment of the dispersal from a source at an arbitrary height while taking account of plume depletion by dry and wet deposition together with the decay of material to successor species. The plume depletion, decay and growth equations are solved in an efficient manner which can accommodate up to eight pollutants (i.e., a parent and seven serial decay products). The code is particularly suitable for applications involving radioactive chain decay or for cases involving chemical species with successor decay products. Arbitrary emission rates can be specified for the members of the chain or, as is commonly the case, a sole emission rate can be specified for the first member. The code uses readily available upper-air wind data for the North American continent and it is therefore intended for the estimation of regional or continental scale dispersion patterns. This code is one of a group of codes, the Computerized Radiological Risk Investigation System (Baes and Miller, 1981), designed to simulate the transport of radionuclides through environmental pathways. 24 references, 5 figures

Trophic position and metabolic rate predict the long-term decay process of radioactive cesium in fish: a meta-analysis.

Directory of Open Access Journals (Sweden)

Hideyuki Doi

Full Text Available Understanding the long-term behavior of radionuclides in organisms is important for estimating possible associated risks to human beings and ecosystems. As radioactive cesium (¹³⁷Cs can be accumulated in organisms and has a long physical half-life, it is very important to understand its long-term decay in organisms; however, the underlying mechanisms determining the decay process are little known. We performed a meta-analysis to collect published data on the long-term ¹³⁷Cs decay process in fish species to estimate biological (metabolic rate and ecological (trophic position, habitat, and diet type influences on this process. From the linear mixed models, we found that 1 trophic position could predict the day of maximum ¹³⁷Cs activity concentration in fish; and 2 the metabolic rate of the fish species and environmental water temperature could predict ecological half-lives and decay rates for fish species. These findings revealed that ecological and biological traits are important to predict the long-term decay process of ¹³⁷Cs activity concentration in fish.

A computer program to calculate nuclide yields in complex decay chain for selection of optimum irradiation and cooling condition

International Nuclear Information System (INIS)

Takeda, Tsuneo

1977-11-01

This report is prepared as a user's input manual for a computer code CODAC-No.5 and provides a general description of the code and instructions for its use. The code represents a modified version of the CODAC-No.4 code. The code developed is capable of calculating radioactive nuclide yields in an any given complex decay and activation chain independent of irradiation history. In this code, eighteen kinds of valuable tables and graphs can be prepared for output. They are available for selection of optimum irradiation and cooling conditions and for other intentions in accordance with irradiation and cooling. For a example, the ratio of a nuclide yield to total nuclide yield depending on irradiation and cooling times is obtained. In these outputs, several kinds of complex and intricate equations and others are included. This code has almost the same input forms as that of CODAC-No.4 code excepting input of irradiation history data. Input method and formats used for this code are very simple for any kinds of nuclear data. List of FORTRAN statements, examples of input data and output results and list of input parameters and its definitions are given in this report. (auth.)

Hamiltonian Markov Chain Monte Carlo Methods for the CUORE Neutrinoless Double Beta Decay Sensitivity

Science.gov (United States)

Graham, Eleanor; Cuore Collaboration

2017-09-01

The CUORE experiment is a large-scale bolometric detector seeking to observe the never-before-seen process of neutrinoless double beta decay. Predictions for CUORE's sensitivity to neutrinoless double beta decay allow for an understanding of the half-life ranges that the detector can probe, and also to evaluate the relative importance of different detector parameters. Currently, CUORE uses a Bayesian analysis based in BAT, which uses Metropolis-Hastings Markov Chain Monte Carlo, for its sensitivity studies. My work evaluates the viability and potential improvements of switching the Bayesian analysis to Hamiltonian Monte Carlo, realized through the program Stan and its Morpho interface. I demonstrate that the BAT study can be successfully recreated in Stan, and perform a detailed comparison between the results and computation times of the two methods.

Fine structure of cluster decays

International Nuclear Information System (INIS)

Dumitrescu, O.

1993-07-01

Within the one level R-matrix approach the hindrance factors of the radioactive decays in which are emitted α and 14 C - nuclei are calculated. The generalization to radioactive decays in which are emitted heavier clusters such as e.g. 20 O, 24 Ne, 25 Ne, 28 Mg. 30 Mg, 32 Si and 34 Si is straightforward. The interior wave functions are supposed to be given by the shell model with effective residual interactions (e.g. the large scale shell model code-OXBASH - in the Michigan State University version for nearly spherical nuclei or by the enlarged superfluid model - ESM - recently proposed for deformed nuclei). The exterior wave functions are calculated from a cluster - nucleus double - folding model potential obtained with the M3Y interaction. As examples of the cluster decay fine structure we analyzed the particular cases of α - decay of 241 Am and 14 C -decay of 233 Ra. Good agreement with the experimental data is obtained. (author). 78 refs, 2 figs, 6 tabs

Handbook of radioactivity measurements procedures. Second edition

International Nuclear Information System (INIS)

Anon.

1985-01-01

This report is concerned with the measurement of radioactivity in general, but specifically it deals with radioactive materials that have become available in the last three decades, from nuclear reactors and particle accelerators, for applications in medicine, scientific research, and industry. It is also concerned with low-level radioactivity measurements for the monitoring of radioactivity in environmental media, such as air and water, in connection with the control of radioactive effluents associated with the production of nuclear power or the use of radionuclides. Included in appendices are nuclear decay data for selected radionuclides and statistics of radioactive decay. An extensive bibliography is also included

Half-lives for proton emission, alpha decay, cluster radioactivity, and cold fission processes calculated in a unified theoretical framework

International Nuclear Information System (INIS)

Duarte, S.B.; Tavares, O.A.P.; Guzman, F.; Dimarco, A.; Garcia, F.; Goncalves, M.

2002-01-01

Half-life values of spontaneous nuclear decay processes are presented in the framework of the Effective Liquid Drop Model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer with Werner-Wheeler's inertia coefficient V MAS /WW. The calculated half-lives of ground-state to ground-state transitions for the proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. Results have shown that the ELDM is a very efficient model to describe these different decay processes in a same, unified theoretical framework. A Table listing the predicted half-life values, τ c is presented for all possible cases of spontaneous nuclear break-up such that -7.30 10 τ c [S] 10 (τ/τ c ) > -17.0, where τ is the total half-life of the parent nucleus. (author)

Anomalous effects of radioactive decay rates and capacitance values measured inside a modified Faraday cage: Correlations with space weather

Science.gov (United States)

Scholkmann, F.; Milián-Sánchez, V.; Mocholí-Salcedo, A.; Milián, C.; Kolombet, V. A.; Verdú, G.

2017-03-01

Recently we reported (Milián-Sánchez V. et al., Nucl. Instrum. Methods A, 828 (2016) 210) our experimental results involving 226Ra decay rate and capacitance measurements inside a modified Faraday cage. Our measurements exhibited anomalous effects of unknown origin. In this letter we report new results regarding our investigation into the origins of the observed effects. We report preliminary findings of a correlation analysis between the radioactive decay rates and capacitance time series and space weather related variables (geomagnetic field disturbances and cosmic-ray neutron counts). A significant correlation was observed for specific data sets. The results are presented and possible implications for future work discussed.

Radioactive decays at limits of nuclear stability

DEFF Research Database (Denmark)

Pfützner, M.; Karny, M.; Grigorenko, L. V.

2012-01-01

, and their relative probabilities. When approaching limits of nuclear stability, new decay modes set in. First, beta decays are accompanied by emission of nucleons from highly excited states of daughter nuclei. Second, when the nucleon separation energy becomes negative, nucleons start being emitted from the ground...

In-trap decay spectroscopy for {beta}{beta} decays

Energy Technology Data Exchange (ETDEWEB)

Brunner, Thomas

2011-01-18

The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in {beta}{beta} decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from {beta} decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and {beta} detection with almost no {beta}-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in {beta}{beta} decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in {beta}{beta} decays. These branches are typically of the order of 10{sup -5} and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating {beta} background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge

In-trap decay spectroscopy for ββ decays

International Nuclear Information System (INIS)

Brunner, Thomas

2011-01-01

The presented work describes the implementation of a new technique to measure electron-capture (EC) branching ratios (BRs) of intermediate nuclei in ββ decays. This technique has been developed at TRIUMF in Vancouver, Canada. It facilitates one of TRIUMF's Ion Traps for Atomic and Nuclear science (TITAN), the Electron Beam Ion Trap (EBIT) that is used as a spectroscopy Penning trap. Radioactive ions, produced at the radioactive isotope facility ISAC, are injected and stored in the spectroscopy Penning trap while their decays are observed. A key feature of this technique is the use of a strong magnetic field, required for trapping. It radially confines electrons from β decays along the trap axis while X-rays, following an EC, are emitted isotropically. This provides spatial separation of X-ray and β detection with almost no β-induced background at the X-ray detector, allowing weak EC branches to be measured. Furthermore, the combination of several traps allows one to isobarically clean the sample prior to the in-trap decay spectroscopy measurement. This technique has been developed to measure ECBRs of transition nuclei in ββ decays. Detailed knowledge of these electron capture branches is crucial for a better understanding of the underlying nuclear physics in ββ decays. These branches are typically of the order of 10 -5 and therefore difficult to measure. Conventional measurements suffer from isobaric contamination and a dominating β background at theX-ray detector. Additionally, X-rays are attenuated by the material where the radioactive sample is implanted. To overcome these limitations, the technique of in-trap decay spectroscopy has been developed. In this work, the EBIT was connected to the TITAN beam line and has been commissioned. Using the developed beam diagnostics, ions were injected into the Penning trap and systematic studies on injection and storage optimization were performed. Furthermore, Ge detectors, for the detection of X-rays, were

Radioactive waste management

International Nuclear Information System (INIS)

Blomek, D.

1980-01-01

The prospects of nuclear power development in the USA up to 2000 and the problems of the fuel cycle high-level radioactive waste processing and storage are considered. The problems of liquid and solidified radioactive waste transportation and their disposal in salt deposits and other geologic formations are discussed. It is pointed out that the main part of the high-level radioactive wastes are produced at spent fuel reprocessing plants in the form of complex aqueous mixtures. These mixtures contain the decay products of about 35 isotopes which are the nuclear fuel fission products, about 18 actinides and their daughter products as well as corrosion products of fuel cans and structural materials and chemical reagents added in the process of fuel reprocessing. The high-level radioactive waste management includes the liquid waste cooling which is necessary for the short and middle living isotope decay, separation of some most dangerous components from the waste mixture, waste solidification, their storage and disposal. The conclusion is drawn that the seccessful solution of the high-level radioactive waste management problem will permit to solve the problem of the fuel cycle radioactive waste management as a whole. The salt deposits, shales and clays are the most suitable for radioactive waste disposal [ru

Semianalytical Solutions of Radioactive or Reactive Transport in Variably-Fractured Layered Media: 1. Solutes

International Nuclear Information System (INIS)

George J. Moridis

2001-01-01

In this paper, semianalytical solutions are developed for the problem of transport of radioactive or reactive solute tracers through a layered system of heterogeneous fractured media with misaligned fractures. The tracer transport equations in the non-flowing matrix account for (a) diffusion, (b) surface diffusion, (c) mass transfer between the mobile and immobile water fractions, (d) linear kinetic or equilibrium physical, chemical, or combined solute sorption or colloid filtration, and (e) radioactive decay or first-order chemical reactions. The tracer-transport equations in the fractures account for the same processes, in addition to advection and hydrodynamic dispersion. Any number of radioactive decay daughter products (or products of a linear, first-order reaction chain) can be tracked. The solutions, which are analytical in the Laplace space, are numerically inverted to provide the solution in time and can accommodate any number of fractured and/or porous layers. The solutions are verified using analytical solutions for limiting cases of solute and colloid transport through fractured and porous media. The effect of important parameters on the transport of 3 H, 237 Np and 239 Pu (and its daughters) is investigated in several test problems involving layered geological systems of varying complexity

A computer method for simulating the decay of radon daughters

International Nuclear Information System (INIS)

Hartley, B.M.

1988-01-01

The analytical equations representing the decay of a series of radioactive atoms through a number of daughter products are well known. These equations are for an idealized case in which the expectation value of the number of atoms which decay in a certain time can be represented by a smooth curve. The real curve of the total number of disintegrations from a radioactive species consists of a series of Heaviside step functions, with the steps occurring at the time of the disintegration. The disintegration of radioactive atoms is said to be random but this random behaviour is such that a single species forms an ensemble of which the times of disintegration give a geometric distribution. Numbers which have a geometric distribution can be generated by computer and can be used to simulate the decay of one or more radioactive species. A computer method is described for simulating such decay of radioactive atoms and this method is applied specifically to the decay of the short half life daughters of radon 222 and the emission of alpha particles from polonium 218 and polonium 214. Repeating the simulation of the decay a number of times provides a method for investigating the statistical uncertainty inherent in methods for measurement of exposure to radon daughters. This statistical uncertainty is difficult to investigate analytically since the time of decay of an atom of polonium 218 is not independent of the time of decay of subsequent polonium 214. The method is currently being used to investigate the statistical uncertainties of a number of commonly used methods for the counting of alpha particles from radon daughters and the calculations of exposure

Radical Abstraction Reactions with Concerted Fragmentation in the Chain Decay of Nitroalkanes

Science.gov (United States)

Denisov, E. T.; Shestakov, A. F.

2018-05-01

Reactions of the type X• + HCR2CH2NO2 → XH + R2C=CH2 + N•O2 are exothermic, due to the breaking of weak C-N bonds and the formation of energy-intensive C=C bonds. Quantum chemistry calculations of the transition state using the reactions of Et• and EtO• with 2-nitrobutane shows that such reactions can be categorized as one-step, due to the extreme instability of the intermediate nitrobutyl radical toward decay with the formation of N•O2. Kinetic parameters that allow us to calculate the energy of activation and rate constant of such a reaction from its enthalpy are estimated using a model of intersecting parabolas. Enthalpies, energies of activation, and rate constants are calculated for a series of reactions with the participation of Et•, EtO•, RO•2, N•O2 radicals on the one hand and a series of nitroalkanes on the other. A new kinetic scheme of the chain decay of nitroalkanes with the participation of abstraction reactions with concerted fragmentation is proposed on the basis of the obtained data.

Apparatus and method for depressurizing, degassing, and affording decay of the radioactivity of weakly radioactive condensates in nuclear power plants

International Nuclear Information System (INIS)

Gross, R.; Plotz, J.

1976-01-01

Described is an apparatus for depressurizing, degassing and affording decay of weakly radioactive condensates in nuclear power plants having a turbine and a main condenser turbine wherein exhaust steam of the turbine is condensed and forms a main condensate, and includes a collecting tank for the condensate situated below the condenser. A plurality of horizontal degassing channels, each having a lateral overflow, are disposed in the upper part of the condensate collecting tank and are filled with the main condensate up to the level of the overflow. At least one feedwater preheater which is heated by bleeder steam from the turbine provides a secondary condensate. Below the overflow height of the degassing channels extend horizontal feed pipes for the secondary condensate. The feed pipes are connected to the output of pressure relieving expanding devices and are provided on their underside with discharge openings for the bubbling of the secondary condensate into the main condensate to thereby degass the main condensate. The condensate collecting tank has mutually offset partitions therein providing an adequately long path for the decay of the main and secondary condensates. The condensate which is discharged from the condensate collecting tank is returned into the cycle as feedwater. Also disclosed is a method of operating the foregoing apparatus

48Ca+249Bk fusion reaction leading to element Z = 117: long-lived α-decaying 270Db and discovery of 266Lr.

Science.gov (United States)

Khuyagbaatar, J; Yakushev, A; Düllmann, Ch E; Ackermann, D; Andersson, L-L; Asai, M; Block, M; Boll, R A; Brand, H; Cox, D M; Dasgupta, M; Derkx, X; Di Nitto, A; Eberhardt, K; Even, J; Evers, M; Fahlander, C; Forsberg, U; Gates, J M; Gharibyan, N; Golubev, P; Gregorich, K E; Hamilton, J H; Hartmann, W; Herzberg, R-D; Heßberger, F P; Hinde, D J; Hoffmann, J; Hollinger, R; Hübner, A; Jäger, E; Kindler, B; Kratz, J V; Krier, J; Kurz, N; Laatiaoui, M; Lahiri, S; Lang, R; Lommel, B; Maiti, M; Miernik, K; Minami, S; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Pang, G K; Papadakis, P; Renisch, D; Roberto, J; Rudolph, D; Runke, J; Rykaczewski, K P; Sarmiento, L G; Schädel, M; Schausten, B; Semchenkov, A; Shaughnessy, D A; Steinegger, P; Steiner, J; Tereshatov, E E; Thörle-Pospiech, P; Tinschert, K; Torres De Heidenreich, T; Trautmann, N; Türler, A; Uusitalo, J; Ward, D E; Wegrzecki, M; Wiehl, N; Van Cleve, S M; Yakusheva, V

2014-05-02

The superheavy element with atomic number Z=117 was produced as an evaporation residue in the (48)Ca+(249)Bk fusion reaction at the gas-filled recoil separator TASCA at GSI Darmstadt, Germany. The radioactive decay of evaporation residues and their α-decay products was studied using a detection setup that allowed measuring decays of single atomic nuclei with half-lives between sub-μs and a few days. Two decay chains comprising seven α decays and a spontaneous fission each were identified and are assigned to the isotope (294)117 and its decay products. A hitherto unknown α-decay branch in (270)Db (Z = 105) was observed, which populated the new isotope (266)Lr (Z = 103). The identification of the long-lived (T(1/2) = 1.0(-0.4)(+1.9) h) α-emitter (270)Db marks an important step towards the observation of even more long-lived nuclei of superheavy elements located on an "island of stability."

The synthesis and decay properties of the heaviest elements

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the 'islands of stability' of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus 208 Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with 48 Ca. In these reactions the decay chains of heavy atoms consisting of sequential α-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first experimental evidence of the existence of domains of stability of superheavy nuclei which substantially extends the boundaries of existence of chemical elements

Half-lives for proton emission, alpha decay, cluster radioactivity, and cold fission processes calculated in a unified theoretical framework

Energy Technology Data Exchange (ETDEWEB)

Duarte, S.B.; Tavares, O.A.P.; Guzman, F.; Dimarco, A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas; Rodriguez, O. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Instituto Superior de Ciencias e Tecnologia Nucleares, La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

2002-01-01

Half-life values of spontaneous nuclear decay processes are presented in the framework of the Effective Liquid Drop Model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer with Werner-Wheeler's inertia coefficient V{sub MAS}/WW. The calculated half-lives of ground-state to ground-state transitions for the proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. Results have shown that the ELDM is a very efficient model to describe these different decay processes in a same, unified theoretical framework. A Table listing the predicted half-life values, {tau}{sub c} is presented for all possible cases of spontaneous nuclear break-up such that -7.30 <{approx_equal} log{sub 10} {tau}{sub c} [S] <{approx_equal} 27.50 and log {sub 10}({tau}/{tau}{sub c}) > -17.0, where {tau} is the total half-life of the parent nucleus. (author)

Preliminary Determination of Natural Radioactivity Levels of the State of Qatar using High-Resolution Gamma-ray Spectrometry

International Nuclear Information System (INIS)

Al-Sulaiti, H.A.; Regan, P.H.; Bradley, D.A.; Matthews, M.; Santawamaitre, T.; Malain, D.

2009-01-01

The State of Qatar is a peninsula with a total area of 11,437 km 2 which lies over a geological formation comprising a sequence of limestone, chalk, clay and gypsum. Establishing a baseline for the radioactivity concentration in Qatar's soil is the main purpose behind the present study. The project is focused on obtaining measurements of representative soil samples from various areas in Qatar to establish concentrations of the 235 U, 238 U and 232 Th natural decay chains and also the long-lived naturally occurring radionuclide 40 K. The 235 U, 238 U, 232 Th and 40 K concentrations have been measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector situated in a low-background environment with a copper inner-plated passive lead shield. A wide range of different gamma-ray energy transitions lines arising from the multiple decay products from the 235 U, 238 U and 232 Th decay chains have been analyzed separately to obtain more statistically significant overall results

Mixed radioactive and chemotoxic wastes (RMW)

International Nuclear Information System (INIS)

Dejonghe, I.P.

1991-01-01

During the first decades of development of nuclear energy, organizations involved in the management of nuclear wastes had their attention focused essentially on radioactive components. The impression may have prevailed that, considering the severe restrictions on radioactive materials, the protection measured applied for radioactive components of wastes would be more than adequate to cope with potential hazards from non radioactive components associated with radioactive wastes. More recently it was acknowledged that such interpretation is not necessarily justified in all cases since certain radioactive wastes also contain non-negligible amounts of heavy metals or hazardous organic components which, either, do not decay, or are subject to completely different decay (decomposition) mechanisms. The main purposes of the present study are to analyze whether mixed radioactive wastes are likely to occur in Europe and in what form, whether one needs a basis for integration for evaluating various forms of toxicity and by which practical interventions possible problems can be avoided or at least reduced. (au)

Schemes of radioactive decay, its interpretations in the scope of the radiological protection

International Nuclear Information System (INIS)

Mohamad, N.; Caro, R.A.; Bergoc, R.M.

1998-01-01

Full text: In our teaching experience we have verified that the interpretation of the symbols of radioactive decay schemes is one of the most difficult subject in the study of radioisotope methodologies for almost all professionals, and specially for those who have no solid background in mathematics or physics. The correct interpretation of decay schemes has fundamental importance for the proper election of measurement conditions and for performing the dosimetric and shielding calculations. Nuclides employed in Nuclear Medicine and Biomedicine are beta, gamma or beta/gamma emitters. Interpretation of decay schemes of beta emitters, by β + , β - or electronic capture are not difficult. In gamma emitting nuclides it is frequent that a particular level of energy is de-excited through more than one gamma transition of a given percentage and energy. On the other hand, it is also frequent that conversion electrons are emitted together with gamma photons, the proportion of which is usually given as the conversion factor, e/γ. The fraction of emitted photons is calculated as: 1 / [1+ (e/γ)], whereas the fraction of emitted conversion electrons is equal to: (e/γ) / [1+ (e/γ)]. Special attention should be given to the post-accommodation mechanism after disintegration in which orbital vacancies are produced: electron conversion or electron capture, in which the emission of X-rays and Auger electrons occur. All this information should be taken into account for the correct choice of measurement conditions, as well as internal and external dose calculations. In the present work we describe the analysis and interpretation of disintegration schemes in general and that of the most employed nuclides in Nuclear Medicine and Biomedicine. (author) [es

Sensitivity Increases for the TITAN Decay Spectroscopy Program

Directory of Open Access Journals (Sweden)

Leach K.G.

2015-01-01

Full Text Available The TITAN facility at TRIUMF has recently initiated a program of performing decay spectroscopy measurements in an electron-beam ion-trap (EBIT. The unique environment of the EBIT provides backingfree storage of the radioactive ions, while guiding charged decay particles from the trap centre via the strong magnetic field. This measurement technique is able to provide a significant increase in detection sensitivity for photons which result from radioactive decay. A brief overview of this device is presented, along with methods of improving the signal-to-background ratio for photon detection by reducing Compton scattered events, and eliminating vibrational noise.

Travel in the depth of radioactivity

International Nuclear Information System (INIS)

1996-09-01

This educational booklet gives a general presentation of radioactivity: origin of natural radioactivity, characteristics of atoms and isotopes, the radioactivity phenomenon, its decay and measurement units, the radiations and their use in medicine, industry, agriculture and food industry, biology etc.. (J.S.)

Puzzling Two-Proton Decay of 67Kr

Science.gov (United States)

Wang, S. M.; Nazarewicz, W.

2018-05-01

Ground-state two-proton (2 p ) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The 2 p decay lifetime and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. The recently measured 2 p decay of 67Kr turned out to be unexpectedly fast. Since 67Kr is expected to be a deformed system, we investigate the impact of deformation effects on the 2 p radioactivity. We apply the recently developed Gamow coupled-channel framework, which allows for a precise description of three-body systems in the presence of rotational and vibrational couplings. This is the first application of a three-body approach to a two-nucleon decay from a deformed nucleus. We show that deformation couplings significantly increase the 2 p decay width of 67Kr; this finding explains the puzzling experimental data. The calculated angular proton-proton correlations reflect a competition between 1 p and 2 p decay modes in this nucleus.

Libraries of decay data and fission product yields in the ABBN-93 constant set

International Nuclear Information System (INIS)

Zabrodskaya, S.V.; Nikolaev, M.N.; Tsibulya, A.M.

2001-01-01

This paper describes three new libraries in the Abb. constant set which are essential for calculating radioactivity: basic decay data, radioactive decay photon spectra and fission product yields. (author)

Ecological transport and radiation doses from ground water borne radioactive matters

International Nuclear Information System (INIS)

Bergman, R.; Bergstroem, U.; Evans, S.

1978-12-01

Turnover of radioactive matter entering the biosphere with ground water has been studied with regard to exposure and dose to critical groups and populations. The main alternatives considered for outflow of radioactive effluents to the biosphere are: outflow in a valley containing wells, outflow to a fresh-water lake, and outflow in a coastal region of the Baltic Sea. Mathematical models of a set of coupled ecosystems on local, regional- intermediate- and global levels have been used for calculations of doses. The intermediate system refers to the Baltic Sea. The mathematical analysis, based on first order kinetics for the exchange of matter in a system according to compartment principles, also includes products in decay chains, i.e. daughter nuclides generated by decay of nuclides under ecological cycling. The time dependent exposures have been studied for certain long-lived nuclides of radiological interest in waste from reprosessed fuel. Dose and dose commitment have been calculted for different release patterns comprising idealised episodes for outflow to the biosphere during short periods and outflow governed by constant leakage from a source on the border between geosphere and biosphere. (author)

Contribution of the radioactive decay to the study of the structure of N=Z nuclei of mass A>70

International Nuclear Information System (INIS)

Longour, Christophe

1999-01-01

Radioactive decay study gives an access to the interaction which rules the β decay process as well as the structure of the nuclear states involved. This work describes the observation of the decay of N = Z nuclei with mass A > 70. For the odd-odd N = Z nuclei 78 Y, 82 Nb and 86 Tc, the decay has been established as superallowed Fermi type transitions. The results pave the way for more precise measurements and extend the mass range nowadays used to understand the behaviour of the weak interaction in the nuclear matter. The observation of the decay of the even-even N = Z 72 Kr leads us to build the Gamow-Teller strength distribution from which some clues about the ground state deformation of this isotope can be obtained. More complete experimental observation and some developments of the calculations used to interpret the distribution of the Gamow-Teller strength are needed. Finally, this work describes the developments and tests of a prototype detector the aim of which to determine the contribution of β particles to energy distribution observed in germanium detector. The tests we have performed show that this prototype can identify and reject 80% of the β particles emitted by a source with a 2,3 MeV end-point. The very satisfactory performances of this prototype need now to be confirmed under experimental conditions. (author)

GAMCAT - a personal computer database on alpha particles and gamma rays from radioactive decay

International Nuclear Information System (INIS)

Tepel, J.W.; Mueller, H.W.

1990-01-01

The GAMCAT database is a compilation of data describing the alpha particles and gamma rays that occur in the radioactive decay of all known nuclides, adapted for IBM Personal Computers and compatible systems. These compiled data have been previously published, and are now available as a compact database. Entries can be retrieved by defining the properties of the parent nuclei as well as alpha-particle and gamma-ray energies or any combination of these parameters. The system provides fast access to the data and has been completely written in C to run on an AT-compatible computer, with a hard disk and 640K of memory under DOS 2.11 or higher. GAMCAT is available from the Fachinformationszentrum Karlsruhe. (orig.)

The Calculation Of Total Radioactivity Of Kartini Reactor Fuel Element

International Nuclear Information System (INIS)

Budisantoso, Edi Trijono; Sardjono, Y.

1996-01-01

The total radioactivity of Kartini reactor fuel element has been calculated by using ORIGEN2. In this case, the total radioactivity is the sum of alpha, beta, and gamma radioactivity from activation products nuclides, actinide nuclides and fission products nuclides in the fuel element. The calculation was based on irradiation history of fuel in the reactor core. The fuel element no 3203 has location history at D, E, and F core zone. The result is expressed in graphics form of total radioactivity and photon radiations as function of irradiation time and decay time. It can be concluded that the Kartini reactor fuel element in zone D, E, and F has total radioactivity range from 10 Curie to 3000 Curie. This range is for radioactivity after decaying for 84 days and that after reactor shut down. This radioactivity is happened in the fuel element for every reactor operation and decayed until the fuel burn up reach 39.31 MWh. The total radioactivity emitted photon at the power of 0.02 Watt until 10 Watt

Decay and Transmutation of Nuclides

CERN Document Server

Aarnio, Pertti A

1999-01-01

We present a computer code DeTra which solves analytically the Bateman equations governing the decay, build-up and transmutation of radionuclides. The complexity of the chains and the number of nuclides are not limited. The nuclide production terms considered include transmutation of the nuclides inside the chain, external production, and fission. Time dependent calculations are possible since all the production terms can be re-defined for each irradiation step. The number of irradiation steps and output times is unlimited. DeTra is thus able to solve any decay and transmutation problem as long as the nuclear data i.e. decay data and production rates, or cross sections, are known.

ELECTRONIC ANALOG COMPUTER FOR DETERMINING RADIOACTIVE DISINTEGRATION

Science.gov (United States)

Robinson, H.P.

1959-07-14

A computer is presented for determining growth and decay curves for elements in a radioactive disintegration series wherein one unstable element decays to form a second unstable element or isotope, which in turn forms a third element, etc. The growth and decay curves of radioactive elements are simulated by the charge and discharge curves of a resistance-capacitance network. Several such networks having readily adjustable values are connected in series with an amplifier between each successive pair. The time constant of each of the various networks is set proportional to the half-life of a corresponding element in the series represented and the charge and discharge curves of each of the networks simulates the element growth and decay curve.

Theoretical predictions for α -decay chains of 118 290 -298Og isotopes using a finite-range nucleon-nucleon interaction

Science.gov (United States)

Ismail, M.; Adel, A.

2018-04-01

The α -decay half-lives of the recently synthesized superheavy nuclei (SHN) are investigated by employing the density dependent cluster model. A realistic nucleon-nucleon (NN ) interaction with a finite-range exchange part is used to calculate the microscopic α -nucleus potential in the well-established double-folding model. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin (WKB) approximation in combination with the Bohr-Sommerfeld quantization condition. The calculated values of α -decay half-lives of the recently synthesized Og isotopes and its decay products are in good agreement with the experimental data. Moreover, the calculated values of α -decay half-lives have been compared with those values evaluated using other theoretical models, and it was found that our theoretical values match well with their counterparts. The competition between α decay and spontaneous fission is investigated and predictions for possible decay modes for the unknown nuclei 118 290 -298Og are presented. We studied the behavior of the α -decay half-lives of Og isotopes and their decay products as a function of the mass number of the parent nuclei. We found that the behavior of the curves is governed by proton and neutron magic numbers found from previous studies. The proton numbers Z =114 , 116, 108, 106 and the neutron numbers N =172 , 164, 162, 158 show some magic character. We hope that the theoretical prediction of α -decay chains provides a new perspective to experimentalists.

Induced radioactivity in the target station and decay tunnel from a 4MW proton beam

CERN Document Server

Agosteo, S; Otto, T; Silari, Marco

2003-01-01

An important aspect of a future CERN Neutrino Factory is the material activation arising from a 2.2 GeV, 4 MW proton beam striking a mercury target. A first estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump has been performed by the Monte Carlo hadronic cascade code FLUKA. The aim is both to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which will have to be disposed of after the facility has ceased operation. This paper discusses the first results of such calculations.

Management of radioactive waste: A review

OpenAIRE

Luis Paulo Sant'ana; Taynara Cristina Cordeiro

2016-01-01

The issue of disposal of radioactive waste around the world is not solved by now and the principal reason is the lack of an efficient technologic system. The fact that radioactive waste decays of radioactivity with time are the main reasons for setting nuclear or radioactive waste apart from the other common hazardous wastes management. Radioactive waste can be classified according to the state of matter and level of radioactivity and this classification can be differently interpreted from co...

Is the basic law of radioactive decay exponential?

International Nuclear Information System (INIS)

Gopych, P.M.; Zalyubovskii, I.I.

1988-01-01

Basic theoretical approaches to the explanation of the observed exponential nature of the decay law are discussed together with the hypothesis that it is not exponential. The significance of this question and its connection with fundamental problems of modern physics are considered. The results of experiments relating to investigation of the form of the decay law are given

Realization of radioactive equilibrium in the KRISS radon chamber

International Nuclear Information System (INIS)

Lee, Mo Sung; Park, Tae Soon; Lee, Jong Man

2013-01-01

The maintenance of radioactive equilibrium between radon and its decay products in a radon chamber is necessary to calibrate radon decay product monitors. In this study, the activity concentrations of radon decay products have been measured, and mosquito-repellent incense has been used to produce aerosol particles in the chamber. Filter papers with 8 μm pore size were used to collect aerosol in the chamber. The activity concentrations of radon decay products have been evaluated by the Modified Tsivoglou Method. The correction factors due to the differences in counting time requirements of the Modified Tsivoglou Method and the time delay between consecutive measurements have been determined. Finally, the radioactive equilibrium has been confirmed by applying the Bateman equation. - Highlights: • The activity concentrations of radon decay products are evaluated by the Modified Tsivoglou Method. • Mosquito-repellent incense is used to produce aerosol particles in the radon chamber. • The radioactive equilibrium in the chamber was achieved within 2 days and confirmed by the Bateman equation

Effects of natural radioactivity on food radioactivity measurement

International Nuclear Information System (INIS)

Ennyu, Atsuhito

2012-01-01

Since the accident of the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Company, groups and individuals including local governments, food manufacturers, distribution circles, retail circles, and citizens are eager to measure the radioactivity of food, in order to confirm the safety of food from the concerns about radioactive contamination. The measurement of radioactivity of food is done by quantitatively determining gamma rays due to radioactive cesium that was incorporated into the biosphere cycle after having been released into the environment. As for the radioactivity measurement of food using gamma-ray spectrometry with a potassium iodide scintillation detector, which is very commonly used, this paper describes the handling method of obtained data, the principle of erroneous detection of radioactive cesium and iodine interrupted by natural radionuclides, and countermeasures for it. Major natural radioactivity sources are uranium series and thorium series. This paper explains gamma rays, which are characteristic in the decay process of uranium series and often affect the measurement of radioactive cesium in food and water. (O.A.)

Study of proton radioactivities

Energy Technology Data Exchange (ETDEWEB)

Davids, C.N.; Back, B.B.; Henderson, D.J. [and others

1995-08-01

About a dozen nuclei are currently known to accomplish their radioactive decay by emitting a proton. These nuclei are situated far from the valley of stability, and mark the very limits of existence for proton-rich nuclei: the proton drip line. A new 39-ms proton radioactivity was observed following the bombardment of a {sup 96}Ru target by a beam of 420-MeV {sup 78}Kr. Using the double-sided Si strip detector implantation system at the FMA, a proton group having an energy of 1.05 MeV was observed, correlated with the implantation of ions having mass 167. The subsequent daughter decay was identified as {sup 166}Os by its characteristic alpha decay, and therefore the proton emitter is assigned to the {sup 167}Ir nucleus. Further analysis showed that a second weak proton group from the same nucleus is present, indicating an isomeric state. Two other proton emitters were discovered recently at the FMA: {sup 171}Au and {sup 185}Bi, which is the heaviest known proton radioactivity. The measured decay energies and half-lives will enable the angular momentum of the emitted protons to be determined, thus providing spectroscopic information on nuclei that are beyond the proton drip line. In addition, the decay energy yields the mass of the nucleus, providing a sensitive test of mass models in this extremely proton-rich region of the chart of the nuclides. Additional searches for proton emitters will be conducted in the future, in order to extend our knowledge of the location of the proton drip line.

The natural radioactivity of the biosphere

Energy Technology Data Exchange (ETDEWEB)

Pertsov, L A

1967-07-01

Of the approximately 1200 isotopes presently known more than 900 are radioactive. The nuclei of these isotopes are unstable and decay spontaneously emitting ionizing gamma-, alpha- or beta-radiation. The overwhelming majority of known radioactive isotopes have been obtained artificially; only a few are natural. Numerous investigations have shown that many of the natural radioactive isotopes can be grouped into three radioactive families. Each such family is characterized by the existence of one long-lived isotope - the family parent, one gaseous isotope of radon, intermediate radioactive decay products and final stable isotopes of atomic weights 206, 207 and 208. No such generic relationship has been established among the remaining natural radioactive isotopes. The purpose of the book, in contrast to some recent review works, is to present, in addition to a summary of reference data characterizing the radioactivity levels of various components of the biosphere, a description of those phenomena and regularities which will apparently make it possible to understand more completely the basic dynamics of the natural radioactivity of the biosphere and, consequently, contribute to a more correct interpretation of radiation-hygiene in each specific case.

The natural radioactivity of the biosphere

International Nuclear Information System (INIS)

Pertsov, L.A.

1967-01-01

Of the approximately 1200 isotopes presently known more than 900 are radioactive. The nuclei of these isotopes are unstable and decay spontaneously emitting ionizing gamma-, alpha- or beta-radiation. The overwhelming majority of known radioactive isotopes have been obtained artificially; only a few are natural. Numerous investigations have shown that many of the natural radioactive isotopes can be grouped into three radioactive families. Each such family is characterized by the existence of one long-lived isotope - the family parent, one gaseous isotope of radon, intermediate radioactive decay products and final stable isotopes of atomic weights 206, 207 and 208. No such generic relationship has been established among the remaining natural radioactive isotopes. The purpose of the book, in contrast to some recent review works, is to present, in addition to a summary of reference data characterizing the radioactivity levels of various components of the biosphere, a description of those phenomena and regularities which will apparently make it possible to understand more completely the basic dynamics of the natural radioactivity of the biosphere and, consequently, contribute to a more correct interpretation of radiation-hygiene in each specific case

Natural radioactivity in environmental studies

International Nuclear Information System (INIS)

Heijnis, H.; Jenkinson, A.; Chisari, R.

1998-01-01

Full text: The use natural radioactivity in environmental studies has proven a very powerful tool to determine the dynamics of both natural and antrophogenic processes in our environment. The use of 14 C in archeology and past climate studies has led to many scientific discoveries (i.e. shroud of Turin and Utze 'the ice-man' from Austria). The use of the 238 U-decay series is of at least equal value to studies in archeology and past climates. Some of the Isotopes studied supplement 14 C (which is limited to 40,000 years) up to 350,000 years and others can be utilized to date very young sediments, which can't be dated by 14 C. The so-called 210 Pb dating method has been used over the past 3 decades to date recent sediment. The method uses the disequilibrium in the 238 U decay chain, caused by the escape of the intermediate daughter 222 Rn (a noble gas) from the earth's crust. In the atmosphere the 222 Rn decays via short-lived daughter isotopes to 210 Pb. This 210 Pb with a very convenient half-life of 22,3 years decays to stable 206 Pb. By measuring the surface activity of a sediment core and subsequent samples at regular intervals one can establish a chronology for the sediment core. By studying the trace metals in these cores, one could deduce a contamination history for the region. Examples of studies supported by AINSE and ANSTO will be given

Ordered kinematic endpoints for 5-body cascade decays

Energy Technology Data Exchange (ETDEWEB)

Klimek, Matthew D. [Theory Group, Department of Physics and Texas Cosmology Center,University of Texas at Austin, 2515 Speedway, Stop C1608, Austin, TX, 78712 (United States)

2016-12-23

We present expressions for the kinematic endpoints of 5-body cascade decay chains proceeding through all possible combinations of 2-body and 3-body decays, with one stable invisible particle in the final decay stage. When an invariant mass can be formed in multiple ways by choosing different final state particles from a common vertex, we introduce techniques for finding the sub-leading endpoints for all indistinguishable versions of the invariant mass. In contrast to short decay chains, where sub-leading endpoints are linearly related to the leading endpoints, we find that in 5-body decays, they provide additional independent constraints on the mass spectrum.

Tracking and Monitoring of Radioactive Materials in the Commercial Hazardous Materials Supply Chain

International Nuclear Information System (INIS)

Walker, Randy M.; Kopsick, Deborah A; Warren, Tracy A; Abercrombie, Robert K.; Sheldon, Frederick T; Hill, David E.; Gross, Ian G; Smith, Cyrus M.

2007-01-01

One of the main components of the Environmental Protection Agency's (EPA) Clean Materials Program is to prevent the loss of radioactive materials through the use of tracking technologies. If a source is inadvertently lost or purposely abandoned or stolen, it is critical that the source be recovered before harm to the public or the environment occurs. Radio frequency identification (RFID) tagging on radioactive sources is a technology that can be operated in the active or passive mode, has a variety of frequencies available allowing for flexibility in use, is able to transmit detailed data and is discreet. The purpose of the joint DOE and EPA Radiological Source Tracking and Monitoring (RadSTraM) project is to evaluate the viability, effectiveness and scalability of RFID technology under a variety of transportation scenarios. The goal of the Phase II was to continue testing integrated RFID tag systems from various vendors for feasibility in tracking radioactive sealed sources which included the following performance objectives: 1. Validate the performance of RFID intelligent systems to monitor express air shipments of medical radioisotopes in the nationwide supply chain, 2. Quantify the reliability of these tracking systems with regards to probability of tag detection and operational reliability, 3. Determine if the implementation of these systems improves manpower effectiveness, and 4. Demonstrate that RFID tracking and monitoring of radioactive materials is ready for large scale deployment at the National level. For purposes of analysis, the test scenario employed in this study utilized the real world commerce supply chain process for radioactive medical isotopes to validate the performance of intelligent RFID tags. Three different RFID systems were assessed from a shipping and packaging perspective, included varied environmental conditions, varied commodities on board vehicles, temporary staging in shipping terminals using various commodities and normal

Radioactivity and decay heat generation in precambrian magmatic rocks (with the South Pamirs as an example)

International Nuclear Information System (INIS)

Batyrmurzaev, A.S.; Alibekov, G.I.; Bekieva, A.A.

2003-01-01

The evaluation of the heat generation share in the results of the long-living radioactive elements (RAE) decay in the Earth surface layers is accomplished on the basis of the data on the uranium and thorium concentration in the precambrian magmatic rocks of the South Pamirs. It was supposed by the calculations, that the value of the heat flux, generated by the rocks, is determined mainly by the RAE content in the Earth upper layer crust itself of 10-15 km. It is shown that the radioheat generation share is within the range of 5-10% from the measured values of the geothermal flows [ru

Decay Spectroscopy for Nuclear Astrophysics: {beta}-delayed Proton Decay

Energy Technology Data Exchange (ETDEWEB)

Trache, L.; Simmons, E.; Spiridon, A.; McCleskey, M.; Roeder, B. T.; Tribble, R. E. [Texas A and M University, College Station, TX 77845 (United States); Saastamoinen, A.; Jokinen, A.; Aysto, J. [University of Jyvaskyla, Jyvaskyla (Finland); Davinson, T.; Woods, P. J. [University of Edinburgh, Edinburgh (United Kingdom); Pollacco, E.; Kebbiri, M. [CEA/IRFU Saclay (France); Pascovici, G. [IKP, Universitaet zu Koeln (Germany)

2011-11-30

Decay spectroscopy is one of the oldest indirect methods in nuclear astrophysics. We have developed at TAMU techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. These allowed us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of {sup 23}Al, {sup 27}P, {sup 31}Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions {sup 22}Na(p,{gamma}){sup 23}Mg(crucial for the depletion of {sup 22}Na in novae), {sup 26m}Al(p,{gamma}){sup 27}Si and {sup 30}P(p,{gamma}){sup 31}S(bottleneck in novae and XRB burning), respectively. More recently we have radically improved the technique using a gas based detector we call AstroBox.

Suicide of EMT-6 tumor cells by decays from radioactively-labelled sensitizer adducts

International Nuclear Information System (INIS)

Roa, W.H.Y.; Chapman, J.D.

1987-01-01

Nitroaromatic radiosensitizers become metabolically bound preferentially to hypoxic cells and at least 10/sup 9/ adducts/cell can be tolerated as non-toxic. EMT-6 tumor cells have been incubated in hypoxia in the presence of /sup 3/H-Misonidazole and /sup 125/I-Azomycin Riboside for various times and the amount of /sup 3/H or /sup 125/I bound/cell was determined. Cells were stored as monolayers at 25 0 C for up to 96 hr to accumulate radioactive decays and transferred at various times to 37 0 C for colony-forming assays. No radiation inactivation was measured in cells which had incorporated at least 10/sup 6/ /sup 3/H or 10/sup 5/ /sup 125/I atoms. Previous studies had shown that -- 1% of MISO adducts to EMT-6 cells was associated with cellular DNA. These data indicate that the radiation-induced damage produced by these quantities of bound /sup 3/H or /sup 125/I causes little or not cell inactivation. The results of current studies to measure the colony-forming ability of sensitizer-labelled cells which have been stored in liquid nitrogen to facilitate the accumulation of more decays will be reported. These data suggest that a ''sensitizer-adduct suicide technique'' as a hypoxic cell selective adjunct to other cancer therapies is not feasible. These data are also instructive for those who attempt to develop radiolabelled ''tumor specific'' antibodies for therapeutic purposes

Gaseous release of radioactive iodine from decaying plants. I. Release following foliar and root uptake

International Nuclear Information System (INIS)

Saas, Arsene; Grauby, Andre

1975-12-01

Iodine uptake by plants is a significant link in the contamination of the food chain. Long half-live iodine was studied considering foliar and root uptake, loss by rain scavenging, residue decay or outgassing in order to assess two aspects of the problem: the importance of outgassing and the effect of the route of transfer on iodine losses. It appeared that iodine release was a function of the vegetal type, there were differences according to the pattern of absorption (via leaf or root) and the processes of iodine release were usually related to biochemical mechanisms [fr

Decay correction methods in dynamic PET studies

International Nuclear Information System (INIS)

Chen, K.; Reiman, E.; Lawson, M.

1995-01-01

In order to reconstruct positron emission tomography (PET) images in quantitative dynamic studies, the data must be corrected for radioactive decay. One of the two commonly used methods ignores physiological processes including blood flow that occur at the same time as radioactive decay; the other makes incorrect use of time-accumulated PET counts. In simulated dynamic PET studies using 11 C-acetate and 18 F-fluorodeoxyglucose (FDG), these methods are shown to result in biased estimates of the time-activity curve (TAC) and model parameters. New methods described in this article provide significantly improved parameter estimates in dynamic PET studies

Two proton decay in 12O

International Nuclear Information System (INIS)

Kumawat, M.; Singh, U.K.; Jain, S.K.; Saxena, G.; Kaushik, M.; Aggarwal, Mamta

2017-01-01

Two-proton radioactivity was observed experimentally in the decay of 45 Fe, 54 Zn and 48 Ni. From then many theoretical studies of one and two-proton radioactivity have been carried out within the framework of different models including RMF+BCS approach for medium mass region. Towards light mass region proton-proton correlations were observed in two-proton decay of 19 Mg and 16 Ne. Recently, different mechanism of two-proton emission from proton-rich nuclei 23 Al and 22 Mg has been investigated and transition from direct to sequential two-proton decay in sd shell nuclei is observed. Encouraged with these recent studies of two proton emission in light mass nuclei, we have applied our RMF+BCS approach for the study of two proton emission in light mass region and in this paper we present our result of two proton emission in 12 O

The real-time fitting of radioactive decay curves. Pt. 3. Counting during sampling

International Nuclear Information System (INIS)

Hartley, B.M.

1994-01-01

An analysis of a least-squares method for the real-time fitting of the theoretical total count function to the actual total count from radioactive decays has been given previously for the case where counting takes place after a sample is taken. The counting may be done in a number of different counting systems which distinguish between different types or energies of radiation emitted from the sample. The method would allow real-time determination of the numbers of atoms and hence activities of the individual isotopes present and has been designated the Time Evolved Least-Squares method (TELS). If the radioactivity which is to be measured exists as an aerosol or in a form where a sample is taken at a constant rate it may be possible to count during sampling and by so doing reduce the total time required to determine the activity of the individual isotopes present. The TELS method is extended here to the case where counting and the evaluation of the activity takes place concurrently with the sampling. The functions which need to be evaluated are derived and the calculations required to implement the method are discussed. As with the TELS method of counting after sampling the technique of counting during sampling and the simultaneous evaluation of activity could be achieved in real-time. Results of testing the method by computer simulation for two counting schemes for the descendants of radon are presented. ((orig.))

Natural radioactivity at CBPP waste pile

International Nuclear Information System (INIS)

Kovac, Jadranka; Marovic, Gordana

2008-01-01

Electrical power requirements will necessitate doubling the present generating capacity in Croatia in the future. As a result, environmental discharges associated with the coal power industry will considerably increase. Burning of coal is one source of enhanced radiation exposure to naturally occurring elements, particularly members of uranium and thorium decay chains. By coal burning (in CBPP at about 1700 C degrees) the activity originating from uranium and thorium is redistributed from underground (where the impact on humanity is nil) and liberated into the environment. Most of the radioactive substances are concentrated in the ash and slag, which are heavy and drop to the bottom of a furnace, lately transported to deposit pile, from where some activity may leach into aquifer, or be dispersed by wind. Lighter fly ash, however, is carried up the chimney and into the atmosphere and irradiates people and contaminates food crops. Also, 222 Rn escapes into the atmosphere during incineration, while the non-gaseous members of the uranium decay series remain in the ash and slag. Extensive investigations have been performed in the coal burning power plant (CBPP) Plomin in Croatia and at deposit pile. A network of radon escalation measurements, in-situ gamma-spectrometric measurements and monitoring of waste pile were organized. The results of the measurements confirm that the ash/slag deposite site are well monitored and involve all the necessary protective measures. All obtained data can be used as a valuable database for future estimations and modeling of the impact of radioactive pollution to the marine environment. (author)

Low radioactivities '85. (The 7th Nuclear Science Colloquium)

International Nuclear Information System (INIS)

1985-01-01

The conference proceedings contain 108 papers. The following topics are dealt with: accelerator mass spectroscopy, rare decays, underground laboratories, low level counting and spectroscopy, double beta-decay experiments, low level detectors, cosmogenic radionuclides and rare events, 14 C counting and applications, 3 H counting and hydrology appllications, natural radioactivity in the environment, gaseous detectors, anthropogenic radionuclides and radioactivity in the environment. (J.P.)

Development of ACBIO: A Biosphere Template Using AMBER for a Potential Radioactive Waste Repository

International Nuclear Information System (INIS)

Lee, Youn Myoung; Hwang, Yong Soo; Kang, Chul Hyung; Hahn, Pil Soo

2005-01-01

Nuclides in radioactive wastes are assumed to be transported in the geosphere by groundwater and probably discharged into the biosphere. Quantitative evaluation of doses to human beings due to nuclide transport in the geosphere and through the various pathways in the biosphere is the final step of safety assessment of the radioactive waste repository. To calculate the flux to dose conversion factors (DCFs) for nuclides appearing at GBIs with their decay chains, a template ACBIO which is an AMBER case file based on mathematical model for the mass transfer coefficients between the compartments has been developed considering material balance among the compartments in biosphere and then implementing to AMBER, a general and flexible software tool that allows to build dynamic compartment models. An illustrative calculation with ACBIO is shown.

Semianalytical solutions of radioactive or reactive tracer transport in layered fractured media

International Nuclear Information System (INIS)

Moridis, G.J.; Bodvarsson, G.S.

2001-01-01

In this paper, semianalytical solutions are developed for the problem of transport of radioactive or reactive tracers (solutes or colloids) through a layered system of heterogeneous fractured media with misaligned fractures. The tracer transport equations in the matrix account for (a) diffusion, (b) surface diffusion (for solutes only), (c) mass transfer between the mobile and immobile water fractions, (d) linear kinetic or equilibrium physical, chemical, or combined solute sorption or colloid filtration, and (e) radioactive decay or first order chemical reactions. Any number of radioactive decay daughter products (or products of a linear, first-order reaction chain) can be tracked. The tracer-transport equations in the fractures account for the same processes, in addition to advection and hydrodynamic dispersion. Additionally, the colloid transport equations account for straining and velocity adjustments related to the colloidal size. The solutions, which are analytical in the Laplace space, are numerically inverted to provide the solution in time and can accommodate any number of fractured and/or porous layers. The solutions are verified using analytical solutions for limiting cases of solute and colloid transport through fractured and porous media. The effect of important parameters on the transport of 3 H, 237 Np and 239 Pu (and its daughters) is investigated in several test problems involving layered geological systems of varying complexity. 239 Pu colloid transport problems in multilayered systems indicate significant colloid accumulations at straining interfaces but much faster transport of the colloid than the corresponding strongly sorbing solute species

Exhaust gas cleaning system for handling radioactive fission and activation gases

International Nuclear Information System (INIS)

Queiser, H.; Schwarz, H.

1975-01-01

An exhaust gas cleaning system utilizing the principle of delaying radioactive gases to permit their radioactive decay to a level acceptable for release to the atmosphere, comprising an adsorbent for adsorbing radioactive gas and a container for containing the adsorbent and for constraining gas to flow through the adsorbent, the adsorbent and the container forming simultaneously an adsorptive delay section and a mechanical delay section, by means of a predetermined ratio of volume of voids in the adsorbent to total volume of the container containing the adsorbent, for delaying radioactive gas to permit its radioactive decay to a level acceptable for release to the atmosphere is described. A method of using an adsorbent for cleaning a radioactive gas containing an isotope which is adsorbed by the adsorbent and containing an isotope whose adsorption by the adsorbent is low as compared to the isotope which is adsorbed and which is short-lived as compared to the isotope which is adsorbed, comprising constraining the gas to flow through the adsorbent with the retention time for the isotope which is adsorbed being at least the minimum for permitting radioactive decay to a level acceptable for release to the atmosphere and with the retention time for the isotope of relatively low adsorption and relatively short life being at least the minimum for permitting radioactive decay to a level acceptable for release to the atmosphere is also described. (U.S.)

Controlled study of the evolution of radon and its decay products in radioactive mine environments

International Nuclear Information System (INIS)

Calizaya A, F.

1985-01-01

This thesis discusses three aspects related to radon emissions and control of radon decay products in mine environments: (1) measurement of the effects of environmental parameters on radiation levels, (2) analysis of the data using ordinary linear regression and transfer function models and (3) prediction of the concentration of radioactive contaminants in the mine air. In-mine and laboratory experiments were conducted to develop the research data. In mine tests were conducted in a bulkhead isolated mine drift containing low grade uranium ore at the Colorado School of Mines, Experimental Mine with the US Bureau of Mines - Spokane Research Center (USBM, SRC) micro-computer based radiation monitoring system. Parameters such as amount of ore, amount of condensation nuclei in the mine air, temperature, air velocity, and barometric pressure were studied. The laboratory tests were conducted in an air-tight radon chamber equipped with a container of the radioactive material, various monitors, and the USBM, SRC Data Acquisition System. The effect of parameters such as ore grade, particle size, rock moisture, air temperature and relative humidity on radon concentrations were measured in the laboratory. Radiation levels, together with parameters affecting these levels, were measured over a period of one year (June 1984-July 1985) both in the laboratory model and in the field

Heavy fragment radioactivity

International Nuclear Information System (INIS)

Silisteanu, I.

1991-06-01

The effect of collective mode excitation in heavy fragment radioactivity (HFR) is explored and discussed in the light of current experimental data. It is found that the coupling and resonance effects in fragment interaction and also the proper angular momentum effects may lead to an important enhancing of the emission process. New useful procedures are proposed for the study of nuclear decay properties. The relations between different decay processes are investigated in detail. We are also trying to understand and explain in a unified way the reaction mechanisms in decay phenomena. (author). 17 refs, 4 figs, 3 tabs

Terms and definitions in the field of radiological technique. Radioactivity. Draft. Begriffe und Benennungen in der radiologischen Technik. Radioaktivitaet. Entwurf

Energy Technology Data Exchange (ETDEWEB)

1978-04-01

Nuclides and their symbols: Nuclide, symbol for nuclides; Nuclear processes: Nuclear transformation, isomeric transition; Radioactive substances; Radiation of radioactive substances: Alpha radiation, beta radiation, k radiation, gamma radiation, conversion electrons, annihilation radiation, neutron radiation; Activity, specific activity, and activity concentration; Characteristic constants of radio nuclides: Decay constant, lifetime, half-life, specific gamma-ray constant, conversion coefficient; Decay series: Radioactive decay series, radioactive equilibrium; Nuclides with special names and symbols: Hydrogen isotopes, nuclides of the natural decay series.

WAD, a program to calculate the heat produced by alpha decay

International Nuclear Information System (INIS)

Jarvis, R.G.; Bretzlaff, C.I.

1982-09-01

The FORTRAN program WAD (Watts from Alpha Decay) deals with the alpha and beta decay chains to be encountered in advanced fuel cycles for CANDU reactors. The data library covers all necessary alpha-emitting and beta-emitting nuclides and the program calculates the heat produced by alpha decay. Any permissible chain can be constructed very simply

Pretreatment method for radioactive iodine-containing liquid wastes and pretreatment device

International Nuclear Information System (INIS)

Wakaida, Yasuo.

1996-01-01

Heretofore, radioactive iodine-containing liquid wastes have been discharged directly to a storing and decaying storage vessel to conduct a water draining treatment. In the present invention, the radioactive iodine-containing liquid wastes to be discharged are not discharged to the storage vessel directly but injected to a filling tank, as a pretreatment, to distinguish whether proteins are mixed in the liquid wastes or not. When proteins are mixed, miscellaneous materials such as proteins are recovered and removed by a protein processing system. When proteins are not mixed, radioactive iodine is recovered and removed directly by an iodine processing system. With such procedures, water draining treatment in the storing and decaying storage vessel is mitigated, and even when the amount of the radioactive iodine-containing liquid wastes is increased, the existent maintaining and decaying storage vessel can be used as it is. Accordingly, a safe water draining treatment with good efficiency can be conducted relative to radioactive iodine-containing liquid wastes at a reduced cost. (T.M.)

Decay of heavy and superheavy nuclei

Indian Academy of Sciences (India)

April 2014 physics pp. 705–715. Decay of heavy and superheavy nuclei ... study on the feasibility of observing α decay chains from the isotopes of the ... studies on 284−286115 and 288−292117 will be a guide to future experiments. .... ratio of the α decay from the ground state of the parent nucleus to the level i of the.

Analysis of numerical solutions for Bateman equations

International Nuclear Information System (INIS)

Loch, Guilherme G.; Bevilacqua, Joyce S.

2013-01-01

The implementation of stable and efficient numerical methods for solving problems involving nuclear transmutation and radioactive decay chains is the main scope of this work. The physical processes associated with irradiations of samples in particle accelerators, or the burning spent nuclear fuel in reactors, or simply the natural decay chains, can be represented by a set of first order ordinary differential equations with constant coefficients, for instance, the decay radioactive constants of each nuclide in the chain. Bateman proposed an analytical solution for a particular case of a linear chain with n nuclides decaying in series and with different decay constants. For more complex and realistic applications, the construction of analytical solutions is not viable and the introduction of numerical techniques is imperative. However, depending on the magnitudes of the decay radioactive constants, the matrix of coefficients could be almost singular, generating unstable and non convergent numerical solutions. In this work, different numerical strategies for solving systems of differential equations were implemented, the Runge-Kutta 4-4, Adams Predictor-Corrector (PC2) and the Rosenbrock algorithm, this last one more specific for stiff equations. Consistency, convergence and stability of the numerical solutions are studied and the performance of the methods is analyzed for the case of the natural decay chain of Uranium-235 comparing numerical with analytical solutions. (author)

Analysis of numerical solutions for Bateman equations; Analise de solucoes numericas para as equacoes de Bateman

Energy Technology Data Exchange (ETDEWEB)

Loch, Guilherme G.; Bevilacqua, Joyce S., E-mail: guiloch@ime.usp.br, E-mail: joyce@ime.usp.br [Universidade de Sao Paulo (IME/USP), Sao Paulo, SP (Brazil). Departamento de Matematica Aplicada. Instituto de Matematica e Estatistica; Hiromoto, Goro; Rodrigues Junior, Orlando, E-mail: rodrijr@ipen.br, E-mail: hiromoto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

2013-07-01

The implementation of stable and efficient numerical methods for solving problems involving nuclear transmutation and radioactive decay chains is the main scope of this work. The physical processes associated with irradiations of samples in particle accelerators, or the burning spent nuclear fuel in reactors, or simply the natural decay chains, can be represented by a set of first order ordinary differential equations with constant coefficients, for instance, the decay radioactive constants of each nuclide in the chain. Bateman proposed an analytical solution for a particular case of a linear chain with n nuclides decaying in series and with different decay constants. For more complex and realistic applications, the construction of analytical solutions is not viable and the introduction of numerical techniques is imperative. However, depending on the magnitudes of the decay radioactive constants, the matrix of coefficients could be almost singular, generating unstable and non convergent numerical solutions. In this work, different numerical strategies for solving systems of differential equations were implemented, the Runge-Kutta 4-4, Adams Predictor-Corrector (PC2) and the Rosenbrock algorithm, this last one more specific for stiff equations. Consistency, convergence and stability of the numerical solutions are studied and the performance of the methods is analyzed for the case of the natural decay chain of Uranium-235 comparing numerical with analytical solutions. (author)

Introduction to naturally occurring radioactive material

Energy Technology Data Exchange (ETDEWEB)

Egidi, P.

1997-08-01

Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. We are also bathed in a sea of natural radiation coming from the sun and deep space. Living systems have adapted to these levels of radiation and radioactivity. But some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. Other activities, such as flying at high altitudes, expose us to elevated levels of NORM. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose

Investigation of the degree of equilibrium of the long-lived uranium-238 decay-chain members in airborne and bulk uranium-ore dusts

International Nuclear Information System (INIS)

Jackson, P.O.; Thomas, C.W.

1982-08-01

The degree of disequilibrium among 238 U decay chain members in some airborne dusts and typical ores has been established by precise radiochemical analyses. This information is necessary to evaluate the lung dose model currently used for estimating the effect of the inhalation of uranium ore dust. The particle size distributions of airborne decay chain components in dusts at one uranium mill have been investigated. Statistically significant disequilibria were observed for 230 Th, 226 Ra, and 210 Pb in both airborne dusts and composite ore samples. With the exception of ore from one mill in the United States, most of the daughter concentrations in powdered ore composites were within 10% of 238 U. In airborne dusts, the concentration of 226 Ra was typically below 238 U; the minimum 226 Ra concentration observed for airborne ore dusts was 56% of equilibrium. A statistically significant particle size dependence was observed for 226 Ra/ 238 U ratios in several airborne dusts collected at a uranium mill

Mixed incineration of RAIW and liquid scintillator waste after storage for decay

International Nuclear Information System (INIS)

Naba, K.; Nakazato, K.; Kataoka, K.

1993-01-01

Most medical radioactive waste is combustible after radioactive decay. Moreover mixed incineration of LLW with biomedical radioactive waste will lessen radiation exposure to the public. This paper describes the total system flowsheet for the processing of liquid scintillator wastes and radioimmunoassay tube wastes containing iodine 125 (after a two-year storage for decay). The process was tested with a 60 kg/hr capacity incinerator from 1987 to 1991; this has been upgraded to a 150 kg/hr incinerator which is used for nonradioactive biomedical waste incineration as well

Alpha decay and cluster decay of some neutron-rich actinide nuclei

Indian Academy of Sciences (India)

2017-02-09

Feb 9, 2017 ... Abstract. Nuclei in the actinide region are good in exhibiting cluster radioactivity. In the present work, the half-lives of α-decay and heavy cluster emission from certain actinide nuclei have been calculated using cubic plus Yukawa plus exponential model (CYEM). Our model has a cubic potential for the ...

Radioactive cesium isotope ratios as a tool for determining dispersal and re-dispersal mechanisms downwind from the Nevada Nuclear Security Site.

Science.gov (United States)

Snyder, Darin C; Delmore, James E; Tranter, Troy; Mann, Nick R; Abbott, Michael L; Olson, John E

2012-08-01

Fractionation of the two longer-lived radioactive cesium isotopes ((135)Cs and (137)Cs) produced by above ground nuclear tests have been measured and used to clarify the dispersal mechanisms of cesium deposited in the area between the Nevada Nuclear Security Site and Lake Mead in the southwestern United States. Fractionation of these isotopes is due to the 135-decay chain requiring several days to completely decay to (135)Cs, and the 137-decay chain less than one hour decay to (137)Cs. Since the Cs precursors are gases, iodine and xenon, the (135)Cs plume was deposited farther downwind than the (137)Cs plume. Sediment core samples were obtained from the Las Vegas arm of Lake Mead, sub-sampled and analyzed for (135)Cs/(137)Cs ratios by thermal ionization mass spectrometry. The layers proved to have nearly identical highly fractionated isotope ratios. This information is consistent with a model where the cesium was initially deposited onto the land area draining into Lake Mead and the composite from all of the above ground shots subsequently washed onto Lake Mead by high intensity rain and wind storms producing a layering of Cs activity, where each layer is a portion of the composite. Copyright © 2012 Elsevier Ltd. All rights reserved.

SCATTER: Source and Transport of Emplaced Radionuclides: Code documentation

International Nuclear Information System (INIS)

Longsine, D.E.

1987-03-01

SCATTER simulated several processes leading to the release of radionuclides to the site subsystem and then simulates transport via the groundwater of the released radionuclides to the biosphere. The processes accounted for to quantify release rates to a ground-water migration path include radioactive decay and production, leaching, solubilities, and the mixing of particles with incoming uncontaminated fluid. Several decay chains of arbitrary length can be considered simultaneously. The release rates then serve as source rates to a numerical technique which solves convective-dispersive transport for each decay chain. The decay chains are allowed to have branches and each member can have a different radioactive factor. Results are cast as radionuclide discharge rates to the accessible environment

New systematics of cluster- and alpha-decay half lives

International Nuclear Information System (INIS)

Poenaru, D.N.; Greiner, W.

1994-01-01

Available as short communication only. The cluster (or 'exotic') radioactivities belong to a rich variety of nuclear decay modes which are phenomena intermediate between fission and alpha decay. In this contribution a single universal curve for the logarithm of the partial half-life for each kind of cluster radioactivity of even-even parent nuclei is presented. This handy relationship reproduces well the up to now 14 even-even half-life measurements within a ratio of 3.86 or rms=0.587 orders of magnitude. Its universality consists in the fact that instead of having different lines for various parent nuclei, like in the 'classical' systematics (Geiger-Nuttall plot) one can get practically only one line for each decay mode. (Author) 1 Fig., 2 Refs

A simple decay-spectroscopy station at CRIS-ISOLDE

Energy Technology Data Exchange (ETDEWEB)

Lynch, K.M., E-mail: kara.marie.lynch@cern.ch [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); EP Department, CERN, CH-1211 Geneva 23 (Switzerland); Cocolios, T.E. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Althubiti, N. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Farooq-Smith, G.J. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom); Gins, W. [KU Leuven, Instituut voor Kern, en Stralingsfysica, BE-3001 Leuven (Belgium); Smith, A.J. [School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom)

2017-02-01

A new decay-spectroscopy station (DSS2.0) has been designed by the CRIS collaboration for use at the radioactive ion beam facility, ISOLDE. With the design optimised for both charged-particle and γ-ray detection, the DDS2.0 allows high-efficiency decay spectroscopy to be performed. The DSS2.0 complements the existing decay-spectroscopy system at the CRIS experiment, and together provide the ability to perform laser-assisted nuclear decay spectroscopy on both ground state and long-lived isomeric species. This paper describes the new decay-spectroscopy station and presents the characterisation studies that have recently been performed.

Introduction to naturally occurring radioactive material

International Nuclear Information System (INIS)

Egidi, P.

1997-01-01

Naturally occurring radioactive material (NORM) is everywhere; we are exposed to it every day. It is found in our bodies, the food we eat, the places where we live and work, and in products we use. Some industrial practices involving natural resources concentrate these radionuclides to a degree that they may pose risk to humans and the environment if they are not controlled. This session will concentrate on diffuse sources of technologically-enhanced (TE) NORM, which are generally large-volume, low-activity waste streams produced by industries such as mineral mining, ore benefication, production of phosphate Fertilizers, water treatment and purification, and oil and gas production. The majority of radionuclides in TENORM are found in the uranium and thorium decay chains. Radium and its subsequent decay products (radon) are the principal radionuclides used in characterizing the redistribution of TENORM in the environment by human activity. We will briefly review other radionuclides occurring in nature (potassium and rubidium) that contribute primarily to background doses. TENORM is found in many waste streams; for example, scrap metal, sludges, slags, fluids, and is being discovered in industries traditionally not thought of as affected by radionuclide contamination. Not only the forms and volumes, but the levels of radioactivity in TENORM vary. Current discussions about the validity of the linear no dose threshold theory are central to the TENORM issue. TENORM is not regulated by the Atomic Energy Act or other Federal regulations. Control and regulation of TENORM is not consistent from industry to industry nor from state to state. Proposed regulations are moving from concentration-based standards to dose-based standards. So when is TENORM a problem? Where is it a problem? That depends on when, where, and whom you talk to exclamation point We will start by reviewing background radioactivity, then we will proceed to the geology, mobility, and variability of these

Kinetics of the chain uranium decay

International Nuclear Information System (INIS)

Zel'dovich, Ya.B.; Khariton, Yu.B.

1984-01-01

The development of chain reaction in uranium mass, when passing through the mass critical value, is studied. It is shown that thermal expanson is a powerful regulating factor, making the limit passing quite safe. The case of convergence of two uranium masses of precritical dimensions is considered in particular. The critical mass value is assessed and it is shown that its gradual increase above the critical value results in the reaction vibrational regime with the period inversely proportional to the square root of uranium supply rate. The role of delaying neutrons in the fission chain reaction development is pointed out

Study of the radiation and radioactivity in dairy formulas

International Nuclear Information System (INIS)

Mireles G, F.; Pinedo V, J.L.; Quirino T, L.L.; Davila R, J.I.; Rios M, C.; Leal A, B.; Lopez del Rio, H.

2006-01-01

The radiation and natural radioactivity is present in the man's food chain, like it is the case of the milk, and it comes from the natural series of radioactive decay of the 238 U, 235 U and 232 Th, and of the 40 K radioisotope. Since the radioisotopes can be found in floor of where its are transferred to the grasses and in the water that serve as food and of drinking to the cows, then to enter the milk and its derived to the human consumption. In this work it is presented the study of the radiation and gamma radioactivity of 40 samples of dairy formulas of the trademarks and presentations more sold in the market of the private and public sectors. The measurements of the gamma ray spectra were carried out with a spectrometry system based on an Hyper pure Germanium detector (HPGe). The detector has a resolution (FWHM) of 1.9 keV for an energy of the gamma ray of 1.332 keV of the 60 Co. This study presents the results of the concentration in activity of dairy formulations of the radioisotopes of interest. Also, the results are related with possible damages to the health. (Author)

MONITORING OF RADIOACTIVITY AT DNURT CAMPUS

Directory of Open Access Journals (Sweden)

L. F. Dolina

2016-06-01

Full Text Available Purpose. The research paper aims to determine radioactive contamination on the territory of campus of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan (DNURT. Methodology. The dosimeters measured the radioactive contamination in different places (points of DNURT campus, focusing on public places. The centres of measurements became dormitories, monuments, stops, main entrances of the new and the old buildings, classrooms, basements, a swimming pool, boiler room and others. Findings. The conducted radiation monitoring for the first time in the history of the University discovered the source of radioactive contamination on DNURT territory and campus. The highest radiation background is observed on three points, namely: the pedestal of the monument, the monument to students-soldiers, the main entrance of the new building (columns. This can be explained by granite materials, which the pedestals and the stairs are made of. Originality. The largest contribution to the total value of annual effective dose of human exposure is made by ionizing radiation sources (IRS of building materials (65 - 70%. The radioactivity level of building materials is determined by the content of natural radionuclides that are included in uranium-radium and thorium decay series (18 and 12 radionuclides as well as potassium-40. Radioactivity of building materials is evaluated by the content of dominant radionuclides radium-226, thorium-232 and potassium-40. Their dominant role is explained by the fact that these long-lived high-energy - emitters are the products of decay of radium-226 in uranium series of and radium-224 in thorium series, exposing radioactive gases (radon-222 and radon-220. Radioactive gases are accumulated in the basements of educational buildings; their decay is accompanied by 100% alpha radiation, which is the most dangerous. Practical value. It is necessary to set radioactivity signs near the objects with high

MeV particles in a decay chain process from laser-induced processes in ultra-dense deuterium D(0)

International Nuclear Information System (INIS)

Holmlid, L.

2015-01-01

The ejection of particles with energy up to 20 MeV u -1 was reported previously from laser-induced processes in ultra-dense deuterium D(0). Studies of the kinetics of particle formation and decay, and of particle penetration through thick plates are now reported. Magnetic deflection is used to remove charged particles like electrons formed at the target. The signals at a collector in the beam at 0.9 m distance and a shadowed loop collector behind a 1.5–4.5 mm thick steel plate at 0.6 m are compared. The signal at the distant collector matches an intermediate particle B in a decay chain A → B → C with formation and decay time constants of 5–15 ns. The signal at the loop collector is delayed relative to the more distant collector, thus showing a delay of the particles penetrating through the steel plate. The signal at this collector is due to pair production with charge cancellation. Compton electrons from gamma radiation are observed at peak current densities of 1 mA cm -2 at the distant collector. (author)

The radioactive earth

International Nuclear Information System (INIS)

Plant, J.A.; Saunders, A.D.

1996-01-01

Uranium, thorium and potassium are the main elements contributing to natural terrestrial radioactivity. The isotopes 238 U, 235 U, 232 Th and 40 K decay with half-lives so long that significant amounts remain in the earth, providing a continuing source of heat. The slow decay of these isotopes also provides the basis for radiometric age dating and isotopic modelling of the evolution of the earth and its crust. There is a complex interplay between their heat production and the processes involved in crust formation. Phenomena such as volcanism, earthquakes, and large-scale hydrothermal activity associated with ore deposition reflect the dissipation of heat energy from the earth, much of which is derived from natural radioactivity. The higher levels of radioactive elements during the early history of the earth resulted in higher heat flow. All three of the radioactive elements are strongly partitioned into the continental crust, but within the crust their distribution is determined by their different chemical properties. The behaviour of U, which has two commonly occurring oxidation states, is more complex than that of Th and K. Uranium deposits are diverse, and are mostly associated with granites, acid volcanics, or detrital sedimentary rocks. The most important U deposits economically are unconformity-type ores of Proterozoic age, in which U is enriched by up to 5 x 10 6 with respect to bulk earth values. In some cases natural radioactivity can be of environmental concern. The most significant risk is posed by accumulations of radon, the gaseous daughter product of U. (author)

Fundamental symmetries and astrophysics with radioactive beams

International Nuclear Information System (INIS)

Vogt, E.

1996-04-01

A major new initiative at TRIUMF pertains to the use of radioactive beams for astrophysics and for fundamental symmetry experiments. Some recent work is described in which the β-decay-followed by alpha particle emission of 16 N was used to find the resonance parameters dominating the alpha particle capture in 12 C and thus to find the astrophysical S-factor of this reaction which is of crucial importance for alpha-particle burning and the subsequent collapse of stars. In some work underway trapped neural atoms of radioactive potassium atoms will be used to study fundamental symmetries of the weak interactions. Trapping has been achieved and soon 38m K decay will be used to search for evidence of scalar interactions and 37 K decay to search for right-handed gauge-bosom interactions. Future experiments are planned to look for parity non-conservation in trapped francium atoms. This program is part of a revitalization for the TRIUMF laboratory accompanied by the construction of the radioactive beam facility (ISAC). (author)

β decay studies of n-rich Cs isotopes with the ISOLDE Decay Station

Science.gov (United States)

Lică, R.; Benzoni, G.; Morales, A. I.; Borge, M. J. G.; Fraile, L. M.; Mach, H.; Madurga, M.; Sotty, C.; Vedia, V.; De Witte, H.; Benito, J.; Berry, T.; Blasi, N.; Bracco, A.; Camera, F.; Ceruti, S.; Charviakova, V.; Cieplicka-Oryńczak, N.; Costache, C.; Crespi, F. C. L.; Creswell, J.; Fernández-Martínez, G.; Fynbo, H.; Greenlees, P.; Homm, I.; Huyse, M.; Jolie, J.; Karayonchev, V.; Köster, U.; Konki, J.; Kröll, T.; Kurcewicz, J.; Kurtukian-Nieto, T.; Lazarus, I.; Leoni, S.; Lund, M.; Marginean, N.; Marginean, R.; Mihai, C.; Mihai, R.; Negret, A.; Orduz, A.; Patyk, Z.; Pascu, S.; Pucknell, V.; Rahkila, P.; Regis, J. M.; Rotaru, F.; Saed-Sami, N.; Sánchez-Tembleque, V.; Stanoiu, M.; Tengblad, O.; Thuerauf, M.; Turturica, A.; Van Duppen, P.; Warr, N.

2017-05-01

Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on 148-150Cs β-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of 149Ba is presented, giving a first insight in the structure of this neutron-rich nucleus.

Transfer of radionuclides at the uranium and thorium decay chains in aquatic and terrestrial environments

International Nuclear Information System (INIS)

Letourneau, C.

1987-04-01

This report examines the transfer of radionuclides from the uranium and thorium decay chains (U-238, Ra-226, Th-232, Th-230, Po-210 and Pb-210) through the aquatic and terrestrial environment. This transfer is characterized by a transfer coefficient; environmental and experimental factors which cause this coefficient to vary are presented and discussed in this report. Furthermore, based on a literature survey, the report indicates the range of coefficients found for the aquatic sector (that is, sediment and freshwater and marine organisms) and for the terrestrial sector (that is, plants and domestic and wild animals). Afterwards, generalisations are formulated on the transfer of the different radionuclides through the multiple environmental compartments. 75 refs

Research on the reliability of measurement of natural radioactive nuclide concentration of U-238

Energy Technology Data Exchange (ETDEWEB)

Cha, Seok Ki; Kim, Gee Hyun [Dept. of Nuclear engineering, Univ. of SeJong, Seoul (Korea, Republic of); Joo, Sun Dong; Lee, Hoon [KoFONS, Seongnam (Korea, Republic of)

2016-12-15

Naturally occurred radioactive materials (NORM) can be found all around us and people are exposed to this no matter what they do or where they live. In this study, two indirect measurement methods of NORM U-238 has been reviewed; one that has used HPGe on the basis of the maintenance, and the other is disequilibrium theory of radioactive equilibrium relationships of mother and daughter nuclide at Decay-chain of NORM U-238. For this review, complicated pre-processing process (Breaking->Fusion->Chromatography->Electron deposit) has been used , and then carried out a comparative research with direct measurement method that makes use of and measures Alpha spectrometer. Through the experiment as above, we could infer the daughter nuclide whose radioactive equilibrium has been maintained with U-238. Therefore, we could find out that the daughter nuclide suitable to be applied to Gamma indirect measurement method was Th-234. Due to Pearson Correlation statistics, we could find out the reliability of the result value that has been analyzed by using Th-234.

Measurement of the absolute activity of alpha or beta emitters by measuring product nuclei (daughter) activity increase or by studing its radioactive decay

International Nuclear Information System (INIS)

Campos, L.C. de.

1981-01-01

A new method for determining absolute activity of alpha or beta emitters by measuring daughter product radioactive decay is presented. The separation method of UX from hexahydrated uranyl nitrate UO 2 (NO 3 ) 2 6H 2 O based on its dissolution in ethyl ether is described and the accuracy of this method is shown. The factors which accuate on total efficiency of a Geiger Mueller detector for beta particles are determined. The possibility to determine the mass of precursor element by daughter nuclei activity is shown. The results are compared with the one obtained by direct measurement of the mass (or number of atoms) of precursor radioactive substance and with theoretical values calculated for isotopes in secular equilibrium. (Author) [pt

Two-proton decays from light to heavy nuclei - Comparison of theory and experiment

International Nuclear Information System (INIS)

Grigorenko, L. V.; Zhukov, M. V.

2009-01-01

Two-proton (2p) radioactivity was predicted by V.I. Goldansky in 1960 [1] as an exclusively quantum-mechanical phenomenon. True three-body decay, in his terms, is a situation where the sequential emission of the particles is energetically prohibited from the ground state of a nucleus and all the final-state fragments are emitted simultaneously. Since the experimental discovery of the 4 6F e two-proton radioactivity in 2002 [2,3], this field has made fast progress. New cases of 2p radioactivity were found for 6 4Z n [4], 1 9M g [5], and, maybe, 4 8N i [6]. The 2p correlations were recently measured for the ground state decays of 4 6F e [7], 1 9M g [5,8], 1 6N e [8], and 6 B e [9]. All these decays exhibit complex correlation patterns. These correlation patterns are well described within the three-cluster theory of two-proton radioactivity (see Ref. [9] and Refs. therein); the example of the 6 B e ground state decay is provided in Fig. 1. The correlations are shown to be sensitive to the details of structure and nuclear interactions. Thus experimental studies of correlations can provide important information about the structure of decaying nuclei. With lifetimes and correlations well described by the theory in a broad range of nuclear masses (6 B e, 1 9M g, and 4 6F e belong to p, s-d, and p-f shells respectively) understanding of the nature of 2p radioactivity is getting now a solid empirical support. This is specially important in the view of astrophysical implementations of the three-body decay theory for the inverse processes of the three-body radiative capture in astrophysics, which seem to be not completely understood so far.(author)

The CARDS array for neutron-rich decay spectroscopy at HRIBF

CERN Document Server

Batchelder, J C; Bingham, C R; Carter, H K; Cole, J D; Fong, D; Garrett, P E; Grzywacz, R; Hamilton, J H; Hartley, D J; Hwang, J K; Krolas, W; Kulp, D C; Larochelle, Y; Piechaczek, A; Ramayya, A V; Rykaczewski, K; Spejewski, E H; Stracener, D W; Tantawy, M N; Winger, J A; Wood, J; Zganjar, E F

2003-01-01

An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (approx 1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection.

The CARDS array for neutron-rich decay spectroscopy at HRIBF

International Nuclear Information System (INIS)

Batchelder, J.C.; Bilheux, J.-C.; Bingham, C.R.; Carter, H.K.; Cole, J.D.; Fong, D.; Garrett, P.E.; Grzywacz, R.; Hamilton, J.H.; Hartley, D.J.; Hwang, J.K.; Krolas, W.; Kulp, D.; Larochelle, Y.; Piechaczek, A.; Ramayya, A.V.; Rykaczewski, K.P.; Spejewski, E.H.; Stracener, D.W.; Tantawy, M.N.; Winger, J.A.; Wood, J.; Zganjar, E.F.

2003-01-01

An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (∼1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection

GALIST, Decay Gamma Spectra Retrieval from ENSDF

International Nuclear Information System (INIS)

Ichimiya, Tsutomu

2002-01-01

Description of program or function: GALIST consists of two main programs, GAMRET and GNOI. - GAMRET retrieves from ENSDF or files with ENSDF-like format gamma rays following radioactive decay. GAMRET uses two auxiliary programs, ENSORT and AMSORT (see below under item 8). - GNOI makes a list of radionuclides and their gamma rays. In the decay data of ENSDF, however, not all gamma-ray intensities are included

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

Science.gov (United States)

Trache, L.; Banu, A.; Hardy, J. C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Spiridon, A.; Tribble, R. E.; Saastamoinen, A.; Jokinen, A.; Äysto, J.; Davinson, T.; Lotay, G.; Woods, P. J.; Pollacco, E.

2012-02-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A&M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23Al, 27P, 31Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22Na(p,γ)23Mg (crucial for the depletion of 22Na in novae), 26mAl(p,γ)27Si and 30P(p,γ)31S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Decay spectroscopy for nuclear astrophysics: β- and β-delayed proton decay

International Nuclear Information System (INIS)

Trache, L; Banu, A; Hardy, J C; Iacob, V E; McCleskey, M; Roeder, B T; Simmons, E; Spiridon, A; Tribble, R E; Saastamoinen, A; Jokinen, A; Äysto, J; Davinson, T; Lotay, G; Woods, P J; Pollacco, E

2012-01-01

In several radiative proton capture reactions important in novae and XRBs, the resonant parts play the capital role. We use decay spectroscopy techniques to find these resonances and study their properties. We have developed techniques to measure beta- and beta-delayed proton decay of sd-shell, proton-rich nuclei produced and separated with the MARS recoil spectrometer of Texas A and M University. The short-lived radioactive species are produced in-flight, separated, then slowed down (from about 40 MeV/u) and implanted in the middle of very thin Si detectors. This allows us to measure protons with energies as low as 200 keV from nuclei with lifetimes of 100 ms or less. At the same time we measure gamma-rays up to 8 MeV with high resolution HPGe detectors. We have studied the decay of 23 Al, 27 P, 31 Cl, all important for understanding explosive H-burning in novae. The technique has shown a remarkable selectivity to beta-delayed charged-particle emission and works even at radioactive beam rates of a few pps. The states populated are resonances for the radiative proton capture reactions 22 Na(p,γ) 23 Mg (crucial for the depletion of 22 Na in novae), 26m Al(p,γ) 27 Si and 30 P(p,γ) 31 S (bottleneck in novae and XRB burning), respectively. Lastly, results with a new detector that allowed us to measure down to about 80 keV proton energy are announced.

Radioactive waste management information for 1993 and record-to-date

International Nuclear Information System (INIS)

Taylor, K.A.

1994-07-01

This document presents detailed data, bar graphs, and pie charts on volume, radioactivity, isotopic identity, origin, and decay status of radioactive waste for the calendar year 1993. It also summarizes the radioactive waste data records compiled from 1952 to present for the Idaho National Engineering Laboratory (INEL). The data presented are from the INEL Radioactive Waste Management Information System

Radioactive waste management information for 1990 and record-to-date

International Nuclear Information System (INIS)

Litteer, D.L.; Peterson, C.N.; Sims, A.M.

1991-07-01

This document presents detailed data and graphics on volume, radioactivity, isotopic identity, origin, and decay status of radioactive waste for the calendar year 1990. It also summarizes the radioactive waste data records compiled from 1952 to present for the Idaho National Engineering Laboratory (INEL). The data presented are from the INEL Radioactive Waste Management Information System (RWMIS)

Rare psi decays

International Nuclear Information System (INIS)

Partridge, R.

1986-01-01

Slightly more than ten years have passed since the psi was discovered, yet the study of psi decays continues to be an active and fruitful area of research. One reason for such longevity is that each successive experiment has increased their sensitivity over previous experiments either by improving detection efficiency or by increasing statistics. This has allowed the observation and, in some cases, detailed studies of rare psi decays. Branching ratios of ≅10-/sup 4/ are now routinely studied, while certain decay channels are beginning to show interesting effects at the 10-/sup 5/ level. Future experiments at the Beijing Electron Positron Collider (BEPC) have the potential for increasing sensitivities by one or two orders of magnitude, thus enabling many interesting studies impossible with current data samples. The author first examines the extent to which psi decays can be used to study electroweak phenomena. The remainder of this work is devoted to the more traditional task of using the psi to study quarks, gluons, and the properties of the strong interaction. Of particular interest is the study of radioactive psi decays, where a number of new particles have been discovered. Recent results regarding two of these particles, the θ(1700) and iota(1450), are discussed, as well as a study of the quark content of the eta and eta' using decays of the psi to vector-pseudoscalar final states

Beta decay of polarized nuclei and the decay asymmetry of 8Li

International Nuclear Information System (INIS)

Bigelow, R.; Freedman, S.J.; Napolitano, J.; Quin, P.A.

1985-01-01

Under certain conditions, it is possible to produce vector-polarized radioactive nuclei in reactions with a polarized projectile and an unpolarized target. Using the intense polarized beams at the University of Wisconsin, the authors have begun a program to study the weak interaction through the beta decay of polarized nuclei produced in this way. Such experiments bear on tests of CVC in light nuclei, sensitive searches for second-class weak currents, and measurements of the weak vector-coupling constant. One may also deduce the values of certain matrix elements. Our effort is presently centering on a study of the energy dependence of the beta-decay asymmetry of 8 Li

Radioactive waste management solutions

International Nuclear Information System (INIS)

Siemann, Michael

2015-01-01

One of the more frequent questions that arise when discussing nuclear energy's potential contribution to mitigating climate change concerns that of how to manage radioactive waste. Radioactive waste is produced through nuclear power generation, but also - although to a significantly lesser extent - in a variety of other sectors including medicine, agriculture, research, industry and education. The amount, type and physical form of radioactive waste varies considerably. Some forms of radioactive waste, for example, need only be stored for a relatively short period while their radioactivity naturally decays to safe levels. Others remain radioactive for hundreds or even hundreds of thousands of years. Public concerns surrounding radioactive waste are largely related to long-lived high-level radioactive waste. Countries around the world with existing nuclear programmes are developing longer-term plans for final disposal of such waste, with an international consensus developing that the geological disposal of high-level waste (HLW) is the most technically feasible and safe solution. This article provides a brief overview of the different forms of radioactive waste, examines storage and disposal solutions, and briefly explores fuel recycling and stakeholder involvement in radioactive waste management decision making

Analysis for the radionuclides of the natural uranium and thorium decay chains with special reference to uranium mine tailings

International Nuclear Information System (INIS)

Lowson, R.T.; Short, S.A.

1986-08-01

A detailed review is made of the experimental techniques that are available, or are in the process of development, for the determination of 238 U, 235 U, 234 U, 231 Pa, 232 Th, 230 Th, 228 Th, 228 Ra, 226 Ra, 223 Ra, 210 Po and 210 Pb. These products of the uranium and thorium decay chains are found in uranium mine tailings. Reference is also made to a procedure for the selective phase extraction of mineral phases from uranium mine tailings

Low level radioactive waste management and discharge policies in Turkey

International Nuclear Information System (INIS)

Oezdemir, T.; Oezdemir, C.; Uslu, I.

2005-01-01

The legal infrastructure in Turkey for the management of low-level radioactive waste covers the liquid, solid and gaseous wastes. Management of these radioactive wastes is briefly described in this paper. Moreover, delay and decay tank systems that are used to collect and store the low level radioactive wastes as a part of low-level radioactive effluent discharge policy are introduced. (author)

Superallowed Fermi β decay studies at TRIUMF-ISAC

Science.gov (United States)

Svensson, C. E.; Dunlop, R.; Finlay, P.; Ball, G. C.; Ettenauer, S.; Leslie, J. R.; Towner, I. S.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Demand, G.; Djongolov, M.; Garnsworthy, A. B.; Garrett, P. E.; Green, K. L.; Glister, J.; Grinyer, G. F.; Hackman, G.; Hadinia, B.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Rand, E. T.; Starosta, K.; Sumithrarachchi, C. S.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A program of high-precision superallowed Fermi β decay studies is being carried out at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. Recent high-precision branching ratio measurements for the superallowed decays of 74Rb and 26Alm, as well as a half-life measurement for 26Alm that is the most precise half-life measurement for any superallowed emitter to date, are reported. These results provide demanding tests of the theoretical isospin symmetry breaking corrections in superallowed Fermi β decays.

Complete decay of radionuclides: Implications for low-level waste disposal in municipal landfills

International Nuclear Information System (INIS)

Meck, R.A.

1996-01-01

The time required for the complete decay of a radioactive source can be quantified by specifying an acceptable probability and using an original derivation. The physical phenomenon of complete decay may be used as the technical basis to change regulations and permit, with public acceptance, the inexpensive disposal of short half-lived radioactive waste into municipal landfills. Current regulations require isolation of trash form the biosphere for 30 years during the post-closure control period for municipal landfills. Thirty years is sufficient time for complete decay of significant quantities of short-lived radionuclides, and there is a large decay capacity in the nation's landfills. As the major generators of low-level radioactive waste with relatively short half-lives, the academic, medical, and research communities likely would benefit most from such regulatory relief. Disposal of such waste is prohibited or costly. The waste must be specially packaged, stored, transported, and disposed in designated repositories. Regulatory relief can be initiated by citizens since the Administrative Procedures Act gives citizens the right to petition for regulatory change. 10 refs., 2 tabs

Waste water plant for radioactive polluted media, for example faeces

International Nuclear Information System (INIS)

Galler, L.

1985-01-01

In order to provide simple transport of radioactive polluted wastewater to a decay container using simple structural means, where aerobic decay is to take place during storage in the decay container, it is proposed that a sub-pressure source should be connected to the place of origin via a pressure-tight and closed decay container and that the gasous fluid extracted by the subpressure source should be returned to the decay container. (orig./PW) [de

Trapping radioactive ions

CERN Document Server

Kluge, Heinz-Jürgen

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning.

Trapping radioactive ions

International Nuclear Information System (INIS)

Kluge, H.-J.; Blaum, K.

2004-01-01

Trapping devices for atomic and nuclear physics experiments with radioactive ions are becoming more and more important at accelerator facilities. While about ten years ago only one online Penning trap experiment existed, namely ISOLTRAP at ISOLDE/CERN, meanwhile almost every radioactive beam facility has installed or plans an ion trap setup. This article gives an overview on ion traps in the operation, construction or planing phase which will be used for fundamental studies with short-lived radioactive nuclides such as mass spectrometry, laser spectroscopy and nuclear decay spectroscopy. In addition, this article summarizes the use of gas cells and radiofrequency quadrupole (Paul) traps at different facilities as a versatile tool for ion beam manipulation like retardation, cooling, bunching, and cleaning

Influence of radioactivity on surface charging and aggregation kinetics of particles in the atmosphere.

Science.gov (United States)

Kim, Yong-Ha; Yiacoumi, Sotira; Lee, Ida; McFarlane, Joanna; Tsouris, Costas

2014-01-01

Radioactivity can influence surface interactions, but its effects on particle aggregation kinetics have not been included in transport modeling of radioactive particles. In this research, experimental and theoretical studies have been performed to investigate the influence of radioactivity on surface charging and aggregation kinetics of radioactive particles in the atmosphere. Radioactivity-induced charging mechanisms have been investigated at the microscopic level, and heterogeneous surface potential caused by radioactivity is reported. The radioactivity-induced surface charging is highly influenced by several parameters, such as rate and type of radioactive decay. A population balance model, including interparticle forces, has been employed to study the effects of radioactivity on particle aggregation kinetics in air. It has been found that radioactivity can hinder aggregation of particles because of similar surface charging caused by the decay process. Experimental and theoretical studies provide useful insights into the understanding of transport characteristics of radioactive particles emitted from severe nuclear events, such as the recent accident of Fukushima or deliberate explosions of radiological devices.

[Current status on storage, processing and risk communication of medical radioactive waste in Japan].

Science.gov (United States)

Watanabe, Hiroshi; Yamaguchi, Ichiro; Kida, Tetsuo; Hiraki, Hitoshi; Fujibuchi, Toshioh; Maehara, Yoshiaki; Tsukamoto, Atsuko; Koizumi, Mitsue; Kimura, Yumi; Horitsugi, Genki

2013-03-01

Decay-in-storage for radioactive waste including that of nuclear medicine has not been implemented in Japan. Therefore, all medical radioactive waste is collected and stored at the Japan Radioisotope Association Takizawa laboratory, even if the radioactivity has already decayed out. To clarify the current situation between Takizawa village and Takizawa laboratory, we investigated the radiation management status and risk communication activities at the laboratory via a questionnaire and site visiting survey in June 2010. Takizawa laboratory continues to maintain an interactive relationship with local residents. As a result, Takizawa village permitted the acceptance of new medical radioactive waste containing Sr-89 and Y-90. However, the village did not accept any non-medical radioactive waste such as waste from research laboratories. To implement decay-in-storage in Japan, it is important to obtain agreement with all stakeholders. We must continue to exert sincere efforts to acquire the trust of all stakeholders.

Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment

Energy Technology Data Exchange (ETDEWEB)

Beeman, J. W. [Lawrence Berkeley National Laboratory, 94720, Berkeley, CA (United States); Bellini, F. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy); Benetti, P. [Dipartimento di Chimica, Università di Pavia, 27100, Pavia (Italy); INFN, Sezione di Pavia, 27100, Pavia (Italy); Cardani, L. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); Physics Department, Princeton University, 08544, Princeton, NJ (United States); Casali, N. [Dipartimento di Fisica, Sapienza Università di Roma, 00185, Rome (Italy); INFN, Sezione di Roma, 00185, Rome (Italy)

2015-12-13

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4·10{sup 22}, 1.3·10{sup 22} and 1.0·10{sup 22} y, respectively, with a 90 % C.L.

Double-beta decay investigation with highly pure enriched {sup 82}Se for the LUCIFER experiment

Energy Technology Data Exchange (ETDEWEB)

Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bellini, F.; Casali, N.; Ferroni, F.; Piperno, G. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); INFN, Sezione di Roma, Rome (Italy); Benetti, P. [Universita di Pavia, Dipartimento di Chimica, Pavia (Italy); INFN, Sezione di Pavia, Pavia (Italy); Cardani, L. [Sapienza Universita di Roma, Dipartimento di Fisica, Rome (Italy); Princeton University, Physics Department, Princeton, NJ (United States); Chiesa, D.; Clemenza, M.; Gironi, L.; Maino, M. [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano Bicocca, Milan (Italy); Dafinei, I.; Orio, F.; Tomei, C.; Vignati, M. [INFN, Sezione di Roma, Rome (Italy); Di Domizio, S. [INFN, Sezione di Genova, Genoa (Italy); Universita di Genova, Dipartimento di Fisica, Genoa (Italy); Giuliani, A. [Centre de Spectrometrie de Masse, Orsay (France); Gotti, C.; Pessina, G.; Previtali, E.; Rusconi, C. [INFN, Sezione di Milano Bicocca, Milan (Italy); Laubenstein, M.; Nisi, S.; Pattavina, L.; Pirro, S.; Schaeffner, K. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (L' Aquila) (Italy); Nagorny, S.; Pagnanini, L. [Gran Sasso Science Institute, L' Aquila (Italy); Nones, C. [SPP Centre de Saclay, CEA, Irfu, Gif-sur-Yvette (France)

2015-12-15

The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of {sup 82}Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched {sup 82}Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3 % enriched {sup 82}Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of {sup 232}Th, {sup 238}U and {sup 235}U are respectively: <61, <110 and <74 μBq/kg at 90 % C.L. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the {sup 82}Se allowed us to establish the most stringent lower limits on the half-lives of the double-beta decay of {sup 82}Se to 0{sub 1}{sup +}, 2{sub 2}{sup +} and 2{sub 1}{sup +} excited states of {sup 82}Kr of 3.4.10{sup 22}, 1.3.10{sup 22} and 1.0.10{sup 22} y, respectively, with a 90 % C.L. (orig.)

Pulsational Pair-instability Model for Superluminous Supernova PTF12dam:Interaction and Radioactive Decay

Energy Technology Data Exchange (ETDEWEB)

Tolstov, Alexey; Nomoto, Ken’ichi; Blinnikov, Sergei; Quimby, Robert [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sorokina, Elena [Sternberg Astronomical Institute, M.V.Lomonosov Moscow State University, 119991 Moscow (Russian Federation); Baklanov, Petr, E-mail: alexey.tolstov@ipmu.jp [Institute for Theoretical and Experimental Physics (ITEP), 117218 Moscow (Russian Federation)

2017-02-01

Being a superluminous supernova, PTF12dam can be explained by a {sup 56}Ni-powered model, a magnetar-powered model, or an interaction model. We propose that PTF12dam is a pulsational pair-instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by a double energy source: radioactive decay of {sup 56}Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra, we use radiation-hydrodynamics calculations of the STELLA code. We found that light curves are well described in the model with 40 M {sub ⊙} ejecta and 20–40 M {sub ⊙} circumstellar medium. The ejected {sup 56}Ni mass is about 6 M {sub ⊙}, which results from explosive nucleosynthesis with large explosion energy (2–3)×10{sup 52} erg. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in the interaction model, all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.

A methodology for the evaluation of the collective dose from radioactivity in terrestrial food chains

International Nuclear Information System (INIS)

Simmonds, J.R.; Linsley, G.S.

1980-02-01

A methodology is described for the evaluation of the collective dose from radioactivity in the terrestrial food chains. It involves the use of an agricultural grid for Great Britain from which the geographical distribution of each of the main cereal, vegetable, fruit and animal products around any given point can be evaluated. A description is given of the procedure by which the grid was assembled. The use of the grid is demonstrated in an example in which the collective doses associated with the milk pathway to man following the routine discharge to air of iodine-131 are compared for two coastal sites in markedly different agricultural regions. (author)

Decay data evaluation project: Evaluation of 52Mn and 52mMn nuclear decay data

Science.gov (United States)

Luca, Aurelian

2017-09-01

All nuclear decay data within the 52Fe-52m,52Mn-52Cr decay chain have been evaluated at IFIN-HH, Romania, as part of an IAEA coordinated research project (F41029) and incorporated into the Decay Data Evaluation Project (DDEP). Both 52Fe and daughter 52Mn are two potentially promising radionuclides to be incorporated into suitable radiopharmaceuticals for PET and SPECT imaging. The decay data evaluation of 52Fe has previously been published and reported to the IAEA Nuclear Data Section. Equivalent DDEP evaluations for 52Mn and 52mMn have also been completed recently, and are presented in summary form below. These improved decay data sets have also been reported to the IAEA in detail, and are highly suitable in dose rate calculations for their application in nuclear medicine.

Progress and Validation of Geant4 Based Radioactive Decay Simulation Using the Examples of Simbol-X and IXO

CERN Document Server

Hauf, S; Pia, M G; Bell, Z; Briel, U; Chipaux, R; Hoffmann, D H H; Kendziorra, E; Laurent, P; Strüder, L; Tenzer, C; Weidenspointer, G; Zoglauer, A

2009-01-01

The anticipated high sensitivity and the science goals of the next generation X-ray space missions, like the International X-ray Observatory or Simbol-X, rely on a low instrumental background, which in turn requires optimized shielding concepts. We present Geant4 based simulation results on the IXO Wide Field Imager cosmic ray proton induced background in comparison with previous results obtained for the Simbol-X LED and HED focal plane detectors. Our results show that an improvement in mean differential background flux compared to actually operating X-ray observatories may be feasible with detectors based on DEPFET technology. In addition we present preliminary results concerning the validation of Geant4 based radioactive decay simulation in space applications as a part of the Nano5 project.

Decay of Hoyle state

Indian Academy of Sciences (India)

2014-11-02

Nov 2, 2014 ... T K RANA, C BHATTACHARYA, S KUNDU, ... of various direct 3α decay mechanisms of the Hoyle state. ... Pramana – J. Phys., Vol. ... FMD predicts a compact triangle shape and LEFT predicts a bent arm chain structure,.

Travel in the depth of radioactivity; Voyage au coeur de la radioactivite

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-09-01

This educational booklet gives a general presentation of radioactivity: origin of natural radioactivity, characteristics of atoms and isotopes, the radioactivity phenomenon, its decay and measurement units, the radiations and their use in medicine, industry, agriculture and food industry, biology etc.. (J.S.)

Nuclear structure from radioactive decay: Annual progress report

International Nuclear Information System (INIS)

Wood, J.L.

1988-01-01

The primary focus this year has been the continuing studies of intruder states and shape coexistence in the neutron-deficient Z /approximately/ 82 region. Most notably, an extensive region of odd-mass nuclei is emerging within which low-lying low-energy electric monopole (EO) transitions occur. This is a completely new nuclear structure phenomenon. The empirical results are based on on-line decay scheme spectroscopy of mass-separated isotopes at UNISOR. In particular, many transition multipolarities are determined from conversion electron subshell ratios observed in γ-gated electron coincidence spectra. This is a completely new nuclear spectroscopic technique. To cite a specific example: our studies of the 185 Au → 185 Pt decay scheme reveal at least 11 transitions with EO components. This is unprecedented in nuclear structure. The role of EO transitions is being pursued in the larger framework of a signature of shape coexistence in nuclei

The new isotope 270110 and its decay products 266Hs and 262Sg

International Nuclear Information System (INIS)

Hofmann, S.; Hessberger, F.P.; Ackermann, D.

2000-11-01

The even-even nucleus 270 110 was synthesized using the reaction 64 Ni + 207 Pb. A total of eight α-decay chains was measured during an irradiation time of seven days. Decay data were obtained for the ground-state and a high spin K isomer. The new nuclei 266 Hs and 262 Sg were identified as daughter products after α decay. Spontaneous fission of 262 Sg terminates the decay chain. The measured data are in agreement with calculations using the macroscopic-microscopic model and with self-consistent HFB calculations with Skyrme-Sly4 interaction. (orig.)

Decay heat uncertainty quantification of MYRRHA

Directory of Open Access Journals (Sweden)

Fiorito Luca

2017-01-01

Full Text Available MYRRHA is a lead-bismuth cooled MOX-fueled accelerator driven system (ADS currently in the design phase at SCK·CEN in Belgium. The correct evaluation of the decay heat and of its uncertainty level is very important for the safety demonstration of the reactor. In the first part of this work we assessed the decay heat released by the MYRRHA core using the ALEPH-2 burnup code. The second part of the study focused on the nuclear data uncertainty and covariance propagation to the MYRRHA decay heat. Radioactive decay data, independent fission yield and cross section uncertainties/covariances were propagated using two nuclear data sampling codes, namely NUDUNA and SANDY. According to the results, 238U cross sections and fission yield data are the largest contributors to the MYRRHA decay heat uncertainty. The calculated uncertainty values are deemed acceptable from the safety point of view as they are well within the available regulatory limits.

Experimental study of ion-induced nucleation by radon decay

International Nuclear Information System (INIS)

He, F.; Hopke, P.K.

1993-01-01

In the environment, the presence of ions from natural radioactivity may increase the rate of new particle formation through ion-induced nucleation. A thermal diffusion cloud chamber (TDCC) has been built to experimentally study ion-induced nucleation where the ions are produced by gaseous radioactive sources. The critical supersaturation values and nucleation rates for methanol, ethanol, 1-propanol, and 1-butanol vapors on ions produced within the volume of the chamber by alpha decay of 222 Rn have been measured quantitatively at various radioactivity concentrations and supersaturations. The presence of ion tracks and the effect of an external electric field were also investigated. The alpha tracks and ion-induced nucleation formed by 222 Rn decay become visible at the critical supersaturation that is below the value needed for homogeneous nucleation. At this supersaturation, the nucleation rates increase substantially with increasing 222 Rn at low activity concentrations, but attain limiting values at higher concentrations. The experimental results indicate that the ionization by radon decay will promote ion-cluster formation and lower the free energy barriers. The formation of visible droplets is strongly dependent on the supersaturation. This study also confirms that the external electric field has a significant effect on the observed rates of nucleation

An automated system for selective fission product separations; decays of 113-115Pd

International Nuclear Information System (INIS)

Meikrantz, D.H.; Gehrke, R.J.; McIsaac, L.D.; Baker, J.D.; Greenwood, R.C.

1981-01-01

A microcomputer controlled radiochemical separation system has been developed for the isolation and study of fission products with half-lives of approx. >= 10 s. The system is based upon solvent extraction with three centrifugal contactors coupled in series, which provides both rapid and highly efficient separations with large decontamination factors. This automated system was utilized to study the radioactive decays of 113-115 Pd via solvent extraction of the Pd-dimethylglyoxime complex from 252 Cf fission products. As a result of this effort, γ-rays associated with the decay of approx. equal to 90-s sup(113,113m)Pd, 149-s 114 Pd and 47-s 115 Pd have been identified. The isotopic assignments to each of these Pd radioactivities have been confirmed from observation of the growth and decay curves of their respective Ag daughters. In addition, previously unreported Ag γ-rays have been assigned; one to the decay of 69-s 113 Ag, and two to the decay of 19-s 115 Ag. (orig.)

Study of ^{14}C Cluster Decay Half-Lives of Heavy Deformed Nuclei

Science.gov (United States)

Shamami, S. Rahimi; Pahlavani, M. R.

2018-01-01

A theoretical model based on deformed Woods-Saxon, Coulomb and centrifugal terms are constructed to evaluate the half-lives for the cluster radioactivity of various super heavy nuclei. Deformation have been applied on all parts of their potential containing nuclear barrier for cluster decay. Also, both parent and daughter nuclei are considered to be deformed. The calculated results of ^{14}C cluster radioactivity half-lives are compared with available experimental data. A satisfactory agreement between theoretical and measured data is achieved. Also, obtained half-lives for each decay family is agreed with Geiger-Nuttall law.

Development of Data Base on Radioactive Discharges and Environmental Activity Levels in Slovenia

International Nuclear Information System (INIS)

Vokal, B.; Krizman, M.

2003-01-01

Radioactivity monitoring in the environment in Slovenia has been currently performed on a regular basis as a monitoring of global radioactive contamination and as operational monitoring in the surroundings of facilities with radioactive discharges. Environmental radioactivity monitoring due to atmospheric nuclear bomb tests in Slovenia started in 1961, while monitoring of radioactive discharges from nuclear facilities in Slovenia started in early 1980s with the extent programmes: in the Krsko nuclear power plant in 1981, in the uranium mining and milling facility at Zirovski vrh (1985) and in the research reactor at Brinje near Ljubljana (1986). Both categories of the results are documented in written reports and sent to the competent authorities, mostly on annual basis. According to the requirements of the European Commission (Commission Recommendation of 8. June 2000 on the application of Article 36 of the Euratom Treaty concerning the monitoring of the levels of the radioactivity in the environment for the purpose of assessing the exposure of the population as a whole (2000/473/Euratom) and Commission Recommendation of 6. December 1999 on the application of Article 37 of the Euratom Treaty (1999/829/Euratom)) and on initiative of the IAEA (IAEA Document International Atomic Energy Agency (IAEA). Project International Data base on Discharges of Radioactive Material to the Environment, 2000) the Slovenian Nuclear Safety Administration (SNSA) started in 2002 with development of the computerised data base on environmental data and radioactive discharges data for the most facilities, specially for the nuclear fuel cycle. At present the environmental database contains the data on global contamination of air, surface waters, tap water sources and food chain (1 37C s, 9 0S r) and also on levels of major natural radionuclides (7 B e, 2 10P b, 2 26R a, 4 0K ). Data base on radioactive discharges for the recent years comprises the activities of fission and activation

First observation of two-proton radioactivity in 48Ni

Energy Technology Data Exchange (ETDEWEB)

Pomorski, M. [University of Warsaw; Pfutzner, M. [University of Warsaw; Dominik, W. [University of Warsaw; Grzywacz, Robert Kazimierz [ORNL; Baumann, T. [Michigan State University, East Lansing; Berryman, J. S. [Michigan State University, East Lansing; Czyrkowski, H. [University of Warsaw; Dabrowski, Ryszard [Warsaw University; Ginter, T. N. [Michigan State University, East Lansing; Johnson, James W [ORNL; Kaminski, A. [PAN, Krakow, Poland; Kuzniak, A. [University of Tennessee, Knoxville (UTK); Larson, N. [Michigan State University, East Lansing; Liddick, S. N. [Michigan State University, East Lansing; Madurga, M [University of Tennessee, Knoxville (UTK); Mazzocchi, C. [University of Warsaw; Miernik, K. [Oak Ridge National Laboratory (ORNL); Miller, D [University of Tennessee, Knoxville (UTK); Paulauskas, S. [University of Tennessee, Knoxville (UTK); Pereira, J. [National Superconducting Cyclotron Laboratory (NSCL); Rykaczewski, Krzysztof Piotr [ORNL; Stolz, A. [Michigan State University, East Lansing; Suchyta, S. [Michigan State University, East Lansing

2011-01-01

The decay of the extremely neutron deficient 48Ni was studied by means of an imaging time projection chamber which allowed the recording of tracks of charged particles. Decays of 6 atoms were observed. Four of them clearly correspond to two-proton radioactivity providing the first direct evidence for this decay mode in 48Ni. Two decays represent -delayed proton emission. The half-life of 48Ni is determined to be T1=2 = 2:1+1:4 0:4 ms.

Decay studies of neutron-deficient lawrencium isotopes

International Nuclear Information System (INIS)

Antalic, S.; Saro, S.; Streicher, B.; Venhart, M.; Hessberger, F.P.; Ackermann, D.; Heinz, S.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Hofmann, S.; Kuusiniemi, P.; Leino, M.; Nishio, K.; Sulignano, B.

2008-01-01

The radioactive decay of the isotopes 254-256 Lr and their daughter products was investigated by means of α, prompt α-γ and delayed conversion electron-γ coincidence spectroscopy. The isotopes were produced using the reaction 48 Ca+ 209 Bi. (orig.)

Determination of the radioactive aerosols transport coefficients generated in open pit uranium mining areas

International Nuclear Information System (INIS)

Azevedo Py Junior, D. de.

1978-01-01

The classical atmospheric transport model is applied to uranium mining operations. Among the transport parameters there is one concerned with radioactive decay, but it does not include the radioactive decay series which is the specific case for uranium. Therefore, an extension of the transport theory is developed and tested, giving results greater than the ones obtained with the classical model, as expected. (author)

Production of $\\Sigma^{0}$ and $\\Omega^{-}$ in Z decays

CERN Document Server

Adam, W; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barate, R; Barbi, M S; Bardin, Dimitri Yuri; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Buys, A; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Djama, F; Dolbeau, J; Dönszelmann, M; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gerdyukov, L N; Gibbs, M; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Pindo, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Solovyanov, O; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Waldner, F; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G

1996-01-01

Reconstructed \\lam\\ baryon decays and photon conversions in DELPHI are used to measure the \\sig\\ production rate from hadronic Z^0 decays at LEP. The number of \\sig\\ decays per hadronic Z decay is found to be: \\begin{center} = \\wffe{0.070}{0.010}{0.010 }{}. \\end{center} \\bigskip The \\Omega^- production rate is similarly measured to be: \\begin{center} = \\wffe{0.0014}{0.0002}{0.0004}{} \\end{center} by a combination of methods using constrained fits to the whole decay chain and particle identification.

Radioactive concentrations in foodstuffs and the ingestion dose from Romanian relevant diets

International Nuclear Information System (INIS)

Ferdes, O.

1994-01-01

Radioactivity measurements of fresh fruits and vegetables, grains (wheat and bread), milk (cheese), meat and meat products from different areas have been done. High-resolution low-level gamma-ray spectrometry, low-level beta total analysis and radiochemical techniques were used. Many radionuclides, both man-made and natural, have been identified. Only a few of them (the man-made Cs, I and Sr as well as the natural 40 K, 7 Be, etc) were of biological importance. In order to predict the ingestion dose, it had to be studied the general pathway of radionuclides to man, including a transfer model to agricultural products and the processes involved in food chain contamination. Modelling the radionuclide behaviour included retention, radioactive decay, metabolic processes and retention after processing. Relevant aspects related to translocation, agricultural practices and food processing were also considered. The human dose due to radioactive intake could be assessed on the basis of a simplified model for radionuclide ingestion and assimilation, considering local conditions and specific diets. As a result the average diets were determined depending on geographical areas (urban, rural, plain and uphill) and age (children, youngsters and adults). The estimated values for yearly ingestion dose vary from a few mSv to tens of mSv (as in the case of 1986 and 1987). (author)

ENDF/B fission product decay data

International Nuclear Information System (INIS)

Rose, P.F.; Burrows, T.W.

1976-08-01

The fission product data have been organized by A-chains in order of ascending A from A = 72 to A = 167. The heading page is followed by more detailed information on the individual members of the chain in order of increasing Z and decreasing metastable state. The detailed information for each member includes the ENDF/B-IV File 1 comments and references if available and applicable to the decay data. Following the comments is a decay scheme of the nuclide tabulating the quantities T/sub 1 / 2 /, Q, branching ratio (BR), (E/sub γ/), (E/sub β/), and (E/sub α/). Uncertainties are given if available in the file. Independent fission yields are given, as well as thermal cross sections and resonance integrals as obtained from ENDF/B-IV. All energies listed in this publication are in keV, and all branching ratios (BR) sum to unity. If there are spectra in the decay data file, the decay scheme is followed by tables of photon, particle, and characteristic radiation. For cases in which the multipolarities could be obtained from the file the tables also contain information on x-rays, conversion electrons, and Auger electrons. Associated with the photon and particle radiation tables are the appropriate average energies per decay for each type of radiation, including neutrino radiation

$\\Upsilon$ production in Z Decays

CERN Document Server

Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Boucham, A; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chen, M; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dorne, I; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hong, S J; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Leggett, C; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Nowak, H; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sassowsky, M; Sauvage, G; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Schneegans, M; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F

1997-01-01

We have searched for evidence of Upsilon production in 3.5 million hadronic Z decays collected by the L3 detector at LEP in 1991-1995. No signals are observed for the decay chain Z -> Upsilon X; Upsilon -> l+l- (l= e, mu), therefore upper limits at the 95% confidence level are set on the following Z branching fractions: BR (Z -> Upsilon(1S) X) Upsilon(2S) X) Upsilon(3S) X) < 9.4 x 10**-5.

Migration of radionuclide chains in subseabed disposal

International Nuclear Information System (INIS)

Ray, A.K.; Nuttall, H.E.

1982-01-01

In this study of subseabed disposal, the two dimensional (axial and radial) migration of radionuclide chains released from a canister located in a sedimentary layer bounded at the top by the ocean and at the bottom by an impermeable basalt zone is analyzed to determine the escape rate of radionuclides into the seawater. Analytical solutions have been derived to represent the transient concentration profiles within the sediment, flux and discharge rates to the water column of each member present in a decay chain. Using the properties of chain members present in actinide decay systems, the effects of half-life, adsorption equilibrium and other relevant parameters are elucidated. 4 figures, 1 table

Radiation doses of inhaled ash from the lignite power plants

International Nuclear Information System (INIS)

Boshevski, Tome; Pop-Jordanov, Jordan; Chaushevski, Anton

1997-01-01

The coal-fired thermal power plants in Macedonia use lignite obtained by surface mining. The lignite contains traces of thorium-232, uranium-238 and uranium-235, which are long-lived natural radioactive isotopes. After lignite combustion, the concentration of these isotopes in the ash is increased. Due to the long life of fossil materials, the decay products are basically grouped in three radioactive chains that are in a semi-steady state, resulting in equal activity of all isotopes from the chain. Among the members of each chain there are α and β emitters followed by γ quanta emitters. The energies of the α and β particles are important for determining the effective dose. The γ quanta provide information about the chain activity and isotope types. Gamma-spectroscopy studies of the ash samples from the power plants in the City of Bitola in Macedonia have confirmed the presence of several radioactive decay products from the uranium and thorium radioactive chains. Using measurements of the radioactivity of the ash in the Bitola region, the total dose from ash inhalation for the population in the Bitola region was calculated and presented in this paper. Also, analysis of the procedure for determining the maximum allowable dose from radioactive contamination of the environment, is described in this paper. (Original)

Radioactive fallout has different effects in Lapland

International Nuclear Information System (INIS)

Rissanen, K.

1993-01-01

The effects of radioactive fallout in Lapland differ from those in southern Finland. The subarctic area is poor in vegetation and nutrients, for which reason radioactive substances enter food chains rapidly. As potassium is low in supply in the north, plants use cesium to replace it. Thus cesium is accumulated very effectively in food chain. When in the food chain, cesium is enriched in reindeer and further in Lapp people, who eat reindeer meat frequently. The Finnish Centre for Radiation and Nuclear Safety established a regional laboratory in northern Finland in the 1970's to monitor radiation and carry out research an the area.(author)

Measurement of relative L X-ray intensity ratio following radioactive decay and photoionization

Energy Technology Data Exchange (ETDEWEB)

Yalcin, P. [Department of Science Education, Faculty of Education, Erzincan University, 24030 Erzincan (Turkey)], E-mail: pasayalcin@hotmail.com; Porikli, S.; Kurucu, Y.; Sahin, Y. [Department of Physics, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey)

2008-05-22

The measurements of the L X-ray intensity ratio I(L{alpha})/I(L{beta}), I(L{alpha})/I(L{gamma}), I(L{alpha})/I(L{iota}), I(L{beta})/I(L{gamma}) and I(L{iota})/I(L{gamma}) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV {gamma}-rays from a filtered radioisotope {sup 241}Am was used, and by the radioactive decay of {sup 160}Tb, {sup 160}Er, {sup 173}Lu, {sup 182}Re, {sup 201}Tl, {sup 203}Pb and {sup 207}Bi. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(L{alpha}/L{beta}), I(L{alpha}/L{gamma}), I(L{alpha}/L{iota}), I(L{beta}/L{gamma}) and I(L{iota}/L{gamma}) intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster-Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results.

Radon-induced surface contaminations in neutrinoless double beta decay and dark matter experiments

International Nuclear Information System (INIS)

Pattavina, L.

2011-01-01

In experiments looking for rare events, like neutrinoless double beta decay (DBD0ν) and dark matter search (DM), one of the main issues is to increase the experimental sensitivity through the material selection and production. The background contribution coming from the materials used for the detector realization has to be minimized. Moreover the net reduction of the background produced by the bulk part of the apparatus has raised concerns about the background contribution coming from the surfaces. Many procedures and techniques were developed during the last years in order to remove and to minimize the presence of possible contaminants on detector surfaces. To succeed in this strategy a big effort was put in defining all possible mechanisms that lead to surface contaminations, as well as specific cleaning procedures, which are able to reduce and control the surface radioactivity. The presence in air and gases of possible radioactive elements that can stick on the detector surfaces can lead to a recontamination process that will vanish all the applied cleaning procedures. Here is presented and analyzed the contribution to the background of rare events experiments like CUORE experiment (DBD0ν) and EDELWEISS experiment (DM) produced by an exposure of their detector components to a big activity of 222 Rn, radioactive daughter isotope from the 238 U chain. (author)

Development of an application simulating radioactive sources; Conception d'une application de simulation de sources radioactives

Energy Technology Data Exchange (ETDEWEB)

Riffault, V.; Locoge, N. [Ecole des Mines de Douai, Dept. Chimie et Environnement, 59 - Douai (France); Leblanc, E.; Vermeulen, M. [Ecole des Mines de Douai, 59 (France)

2011-05-15

This paper presents an application simulating radioactive gamma sources developed in the 'Ecole des Mines' of Douai (France). It generates raw counting data as an XML file which can then be statistically exploited to illustrate the various concepts of radioactivity (exponential decay law, isotropy of the radiation, attenuation of radiation in matter). The application, with a spread sheet for data analysis and lab procedures, has been released under free license. (authors)

EDISTR: a computer program to obtain a nuclear decay data base for radiation dosimetry

International Nuclear Information System (INIS)

Dillman, L.T.

1980-01-01

This report provides documentation for the computer program EDISTR. EDISTR uses basic radioactive decay data from the Evaluated Nuclear Structure Data File developed and maintained by the Nuclear Data Project at the Oak Ridge National Laboratory as input, and calculates the mean energies and absolute intensities of all principal radiations associated with the radioactive decay of a nuclide. The program is intended to provide a physical data base for internal dosimetry calculations. The principal calculations performed by EDISTR are the determination of (1) the average energy of beta particles in a beta transition, (2) the beta spectrum as function of energy, (3) the energies and intensities of x-rays and Auger electrons generated by radioactive decay processes, (4) the bremsstrahlung spectra accompanying beta decay and monoenergetic Auger and internal conversion electrons, and (5) the radiations accompanying spontaneous fission. This report discusses the theoretical and empirical methods used in EDISTR and also practical aspects of the computer implementation of the theory. Detailed instructions for preparing input data for the computer program are included, along with examples and discussion of the output data generated by EDISTR

Fine structure in the cluster decays of the translead nuclei

International Nuclear Information System (INIS)

Dumitrescu, O.; Cioaca, C.

1994-06-01

Within the one level R-matrix approach several hindrance factors for the radioactive decays in which are emitted α and other nuclei (such as 14 C and 20 O) are calculated. The interior wave functions are supposed to be given by the shell model with effective residual interactions. The exterior wave functions are calculated from a cluster - nucleus double - folding model potential with the M3Y interaction. As examples of the cluster decay fine structure we analyzed the particular cases of α - decay of 255 Fm, 14 C - decay of 223 Ra and 20 O - decay of 229 Th and 225 Fm. Good agreement with the experimental data is obtained. (author). 38 refs, 6 tabs

Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements

International Nuclear Information System (INIS)

Álvarez, V; Cárcel, S; Cervera, A; Díaz, J; Ferrario, P; Bandac, I; Bettini, A; Castel, J; Cebrián, S; Dafni, T; Borges, F I G M; Conde, C A N; Dias, T H V T; Fernandes, L M P; Freitas, E D C; Egorov, M; Gehman, V M; Esteve, R; Evtoukhovitch, P; Ferreira, A L

2013-01-01

The ''Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136 Xe, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr and apos;aneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.

K concentration in seven rice varieties and two infusions (coffee and tea) determined by 40K-40Ar radioactive decay

International Nuclear Information System (INIS)

Navarrete, J.M.; Cabrera, L.; Martinez, T.

2005-01-01

As a result of the event occurred in Mexico about 20 years ago, by which milk powder contaminated with 137 CS was imported from an European country after the Chernobyl accident, a legal disposition was set up in the country in order to certify the absence of radioactive contamination by gamma emitters, performing gamma spectroscopy to every foodstuff sample either imported or to be exported. In this process is always detected the X rays (1461 KeV) natural radiation emitted by 11% of 40 K nucleus decaying to 40 Ar by EC. So, when the counts accumulated during a detection time from 12 to 24 hours in a low background scintillation detection system are expressed as cps, corrected for background and divided by the sample weight (g), detection efficiency (%), decay yielding (0.11) and constant specific activity of elementary K(31.19 Bq/gK), the K concentration in the sample .is obtained. This paper reports the results found in seven rice varieties and two more vegetables, coffee and tea, including the K fractions passing to infusions, as well as are discussed similarities and differences related to K concentration and the advantages of the method.

Final report on the project research 'assessment of radiation exposure of the public to radioactivities related to the environment and food chain'. April 1988 - March 1992

International Nuclear Information System (INIS)

1994-03-01

This publication is the collection of the reports on the project research 'Assessment of Radiation Exposure of the Public to Radioactivities Related to the Environment and Food Chain'. The 16 of the reports are indexed individually. (J.P.N.)

Radioactive tracer studies of soil and litter arthropod food chains. Progress report, November 1, 1978-October 31, 1979

International Nuclear Information System (INIS)

Crossley, D.A. Jr.

1979-01-01

Research on soil and litter arthropod food chains, concerning measurement of nutrient flow using radioisotope techniques and investigations of the role of soil arthropods as regulators of the ecosystem-level processes of decomposition and mineralization of nutrients is described. Laboratory measurements of radiotracer turnover by predaceous macroarthropods are reported, as well as the status of research with microarthropod turnover of radioactive tracers. Implications of results are evaluated in context of current understanding of nutrient flows along arthropod food chains. The interactions of soil fauna and mycorrhizal fungi are also under investigation. Field work has been completed on granitic outcrop projects, and a synthesis of results is summarized. Input-output budgets revealed that granitic outcrop island ecosystems are essentially in balance as regards nutrient flows. The ecosystems showed a strong resistance component of stability, as opposed to resilience, following an applied chemical perturbation and a natural one

Radioactive tracer studies of soil and litter arthropod food chains. Progress report, November 1, 1978-October 31, 1979

Energy Technology Data Exchange (ETDEWEB)

Crossley, Jr, D A

1979-07-15

Research on soil and litter arthropod food chains, concerning measurement of nutrient flow using radioisotope techniques and investigations of the role of soil arthropods as regulators of the ecosystem-level processes of decomposition and mineralization of nutrients is described. Laboratory measurements of radiotracer turnover by predaceous macroarthropods are reported, as well as the status of research with microarthropod turnover of radioactive tracers. Implications of results are evaluated in context of current understanding of nutrient flows along arthropod food chains. The interactions of soil fauna and mycorrhizal fungi are also under investigation. Field work has been completed on granitic outcrop projects, and a synthesis of results is summarized. Input-output budgets revealed that granitic outcrop island ecosystems are essentially in balance as regards nutrient flows. The ecosystems showed a strong resistance component of stability, as opposed to resilience, following an applied chemical perturbation and a natural one (drought).

Development of an application simulating radioactive sources

International Nuclear Information System (INIS)

Riffault, V.; Locoge, N.; Leblanc, E.; Vermeulen, M.

2011-01-01

This paper presents an application simulating radioactive gamma sources developed in the 'Ecole des Mines' of Douai (France). It generates raw counting data as an XML file which can then be statistically exploited to illustrate the various concepts of radioactivity (exponential decay law, isotropy of the radiation, attenuation of radiation in matter). The application, with a spread sheet for data analysis and lab procedures, has been released under free license. (authors)

Radioactive waste management information, 1982 summary and record-to-date

International Nuclear Information System (INIS)

Cassidy, G.B.

1983-07-01

This document summarizes radioactive waste data records for the Idaho National Engineering Laboratory (INEL) compiled since 1952. Kinds of information include volume, radioactivity, isotopic identity, origin, and decay status. The radioactive waste data presented was obtained from the INEL Radioactive Waste Management Information System (RWMIS). This report is updated annually to incorporate waste management data for the current year and reflects changes in previous annual reports. Changes are made to more accurately reflect the current status of waste operations at the INEL

Method and apparatus for removing radioactive gases from a nuclear reactor

International Nuclear Information System (INIS)

Frumerman, R.; Brown, W.W.

1975-01-01

A description is given of a method for removing radioactive gases from a nuclear reactor including the steps of draining coolant from a nuclear reactor to a level just below the coolant inlet and outlet nozzles to form a vapor space and then charging the space with an inert gas, circulating coolant through the reactor to assist the release of radioactive gases from the coolant into the vapor space, withdrawing the radioactive gases from the vapor space by a vacuum pump which then condenses and separates water from gases carried forward by the vacuum pump, discharging the water to a storage tank and supplying the separated gases to a gas compressor which pumps the gases to gas decay tanks. After the gases in the decay tanks lose their radioactive characteristics, the gases may be discharged to the atmosphere or returned to the reactor for further use

Nano size Aerosols of Radon Decay Products in Various Environments

International Nuclear Information System (INIS)

Vaupotic, J.

2008-01-01

The radioactive noble gas radon (222Rn, alpha decay, t 1/2 = 3.82 days) is always accompanied by its short-lived decay products (RnDP): 218Po (alpha decay, t 1/2 = 3.10 min), 214Pb (beta/gamma decay, t 1/2 = 26.8 min), 214Bi (beta/gamma decay, t 1/2 = 19.9 min), and 214Po (alpha decay, t 1/2 = 164 μs). In indoor and outdoor air, they appear as unattached RnDP in the form of clusters in the size range 0.5-3 nm and as attached RnDP between 200 and 800 nm. Because of plate-out of aerosols on the walls and floor of a room, as well as air movement and entry of fresh air, radioactive equilibrium between RnDP and Rn in indoor air is only partly achieved and is expressed as a fraction between 0 and 1, called the equilibrium factor, F. Birchall and James elaborated a dosimetric approach to calculate the dose conversion factor, DCF D , based on f un . In this paper, the results of our studies on fun in 29 rooms of kindergartens and 26 rooms of elementary and high schools, at the lowest point and the railway station in the Postojna Cave, and in 4 rooms in wineries in Slovenia are reported, and DCF D values based on the Porstendorfer formulae are discussed and compared with the DCF E value recommended by ICRP-65

Noncharacteristic half-lives in radioactive decay

International Nuclear Information System (INIS)

Corral, Alvaro; Font, Francesc; Camacho, Juan

2011-01-01

Half-lives of radionuclides span more than 50 orders of magnitude. We characterize the probability distribution of this broad-range data set at the same time that we explore a method for fitting power laws and testing goodness-of-fit. It is found that the procedure proposed recently by Clauset et al.[SIAM Rev. 51, 661 (2009)] does not perform well as it rejects the power-law hypothesis even for power-law synthetic data. In contrast, we establish the existence of a power-law exponent with a value around 1.1 for the half-life density, which can be explained by the sharp relationship between decay rate and released energy, for different disintegration types. For the case of alpha emission, this relationship constitutes an original mechanism of power-law generation.

Uranium, thorium and their decay products in human food-chain

International Nuclear Information System (INIS)

Jeambrun, M.

2012-01-01

Uranium, thorium and their decay products are present in trace amounts in all rocks on Earth. Weathering, Mechanisms of soil formation and soil-plant transfers lead to the presence of these radionuclides in all the components of the environment and, through the food-chain transfers, they are also present in animals and men. The objective of this study consists in improving the knowledge on the levels and the variability of the activities of these radionuclides in various foodstuffs and on their sources and transfers. This study is based on the geological variability of the studied sites (granitic, volcanic and alluvial areas) where various foodstuffs are sampled (vegetables, cereals, meat, eggs and dairy products). The possible sources of radionuclides (irrigation waters and soils for plants; water, food and soils for animals) are also sampled in order to study their contribution to the measured activities in the foodstuffs. The results obtained present high variability of the activities in plants, less pronounced in animal products. For plants, the main radionuclide source seems to be the crop soils. Irrigation water, soil particle resuspension and their adhesion to plant surface seems to be important in some cases. For the activities in animal products, a significant contribution of the soil to thorium activity was highlighted. Water contribution to uranium activity in meat and eggs is an area worth further researches. Thus, this study of the possible sources of radionuclides highlights the importance of their role in the understanding of the radionuclide transfers to foodstuffs. (author)

Gamma spectrometry; level schemes

International Nuclear Information System (INIS)

Blachot, J.; Bocquet, J.P.; Monnand, E.; Schussler, F.

1977-01-01

The research presented dealt with: a new beta emitter, isomer of 131 Sn; the 136 I levels fed through the radioactive decay of 136 Te (20.9s); the A=145 chain (β decay of Ba, La and Ce, and level schemes for 145 La, 145 Ce, 145 Pr); the A=47 chain (La and Ce, β decay, and the level schemes of 147 Ce and 147 Pr) [fr

Automated generation of burnup chain for reactor analysis applications

International Nuclear Information System (INIS)

Tran Viet Phu; Tran Hoai Nam; Akio Yamamoto; Tomohiro Endo

2015-01-01

This paper presents the development of an automated generation of a new burnup chain for reactor analysis applications. The JENDL FP Decay Data File 2011 and Fission Yields Data File 2011 were used as the data sources. The nuclides in the new chain are determined by restrictions of the half-life and cumulative yield of fission products or from a given list. Then, decay modes, branching ratios and fission yields are recalculated taking into account intermediate reactions. The new burnup chain is output according to the format for the SRAC code system. Verification was performed to evaluate the accuracy of the new burnup chain. The results show that the new burnup chain reproduces well the results of a reference one with 193 fission products used in SRAC. Further development and applications are being planned with the burnup chain code. (author)

Physical limits on steam generation by radioactive decay heat

International Nuclear Information System (INIS)

Chesnut, D.A.

1991-12-01

This report briefly discusses the possibilities that flood water contacting the hot radioactive waste and rock at Yucca Mountain could produce enough steam to lift the top of the mountain off the repository

Radioactive contamination in the environment and its transfer in food chain pathways

International Nuclear Information System (INIS)

Raja Rajan, A.; Meena, S.; Balamurugan, J.; Jegadeeswari, P.V.

2017-01-01

Radioactive material occurs naturally in the soil, rocks, water, air, and vegetation. The major radionuclides of concern for terrestrial radiation are potassium, uranium and thorium. Each of these sources has been decreasing in activity since the birth of the Earth so that our present dose from 40 K is about ½ what it would have been at the dawn of life on Earth. Some of the elements that make up the human body have radionuclides such as 40 K; thus, there is also a very small amount of internal radiation. Radon gas seeps out of uranium-containing soils found across most of the world and may concentrate in wellsealed homes. It is often the single largest contributor to an individual's background radiation dose. As nuclear facilities are not normally sited in densely populated areas, the adjacent land is likely to be agricultural. Knowledge about the form in which the radionuclides are present in the soil and the patterns of their migration in the environment and food chain can provide the foundation for technical planning

Proposal of traceability chain for direct measurements of radioactive contamination in Cuba

International Nuclear Information System (INIS)

Walwyn Salas, Gonzalo; Tamayo Garcia, Jose A.; Cornejo Diaz, Nestor

2008-01-01

The measurements of the radioactive surface contamination are common used to demonstrate the compliance with safety regulations at national level. It is mandatory that those measurements are traceable to national standards through the suitable calibration of the monitors used for survey. In Cuba, there is not a harmonized methodology for evaluation of contamination from direct measurements and no standardized calibration service for portable monitors is routinely provided to users. The Secondary Standard Dosimetry Laboratory of Cuba has recently established the calibration service of contamination monitors in terms of instrument efficiency using the reference sources of known emission rate per unit area in accordance with international normative ISO 8769. In the present paper, is proposed a traceable scheme of direct measurements of contamination that involve the calibration at the laboratory level using multi-source method and the evaluation of contaminations at user level in terms of activity per unit area. Some improvements from the previous single-source method of calibration are explained in order to support the advantages that offer the new chain for those measurements in the country. (author)

The problem in 180 deg data sampling and radioactivity decay correction in gated cardiac blood pool scanning using SPECT

International Nuclear Information System (INIS)

Ohtake, Tohru; Watanabe, Toshiaki; Nishikawa, Junichi

1986-01-01

In cardiac blood pool scanning using SPECT, half 180 deg data collection (HD) vs. full 360 deg data collection (FD) and Tc-99m decay are problems in quantifying the ejection count (EC) (end-diastolic count - end-systolic count) of both ventricles and the ratio of the ejection count of the right and left ventricles (RVEC/LVEC). We studied the change produced by altering the starting position of data sampling in HD scans. In our results of phantom and 4 clinical cases, when the cardiac axis deviation was not large and there was not remarkable cardiac enlargement, the change in LVEC, RVEC and RVEC/LVEC was small (1 - 4 %) within 12 degree change of the starting position, and the difference between the results of HD scan with a good starting position (the average of LV peak and RV peak) and FD scan was not large (less than 7 %). Because of this, we think HD scan can be used in those cases. But when the cardiac axis deviation was large or there was remarkable cardiac enlargement, the change of LVEC, RVEC and RVEC/LVEC was large (more than 10 %) even within 12 degree change of the starting position. So we think FD scan would be better in those cases. In our results of 6 patients, the half-life of Tc-99m labeled albumin in blood varied from 2 to 4 hr (3.03 ± 0.59 hr, mean ± s.d.). Using a program for radioactivity (RA) decay correction, we studied the change in LVEC, RVEC and LVEC/RVEC in 11 cases. When RA decay correction was performed using a halflife of 3.0 hr, LVEC increased 7.5 %, RVEC increased 8.7 % and RVEC/LVEC increased 0.9 % on the average in HD scans of 8 cases (LPO to RAO, 32 views, 60 beat/1 view). We think RA decay correction would not be needed in quantifying RVEC/LVEC in most cases because the change of RVEC/LVEC was very small. (author)

Analytical Modeling of the Pseudo-Colloid Migration with the Band release Boundary Condition in the Fractured Porous Media

International Nuclear Information System (INIS)

Jeong, Miseon; Kang, Chulhyung; Hwang, Yongsoo

2011-01-01

Many papers have already dealt with the problem of the radionuclide transport in various fractured porous systems, but without discussing daughter products. However, natural radionuclides may decay to radioactive daughter muscled, which may travel farther than the the parent nuclides. It is considered the multi-member decay chain of the actinide nuclide with the band release inlet boundary condition in a fractured porous rock. In this paper, it is developed the pseudo-colloid migration with the band release inlet boundary conditions with multi-member decay chains in a fractured porous matrix. It is obtained a semi-analytical solution for the multi-member decay chains as a canonical form. As one can expected, the colloid has significantly important influence to the radionuclide transport in the geologic system and the decay chain also isn't neglecting. The concept of deep geological disposal of high-level radioactive waste has been widely accepted at many countries. The repositories aim mainly to prevent the radionuclides form migrating to the biosphere through any one of many pathways. Fractures can act as main pathways for radionuclide transport because of their relatively high permeabilities

Forensic microanalysis of Manhattan Project legacy radioactive wastes in St. Louis, MO.

Science.gov (United States)

Kaltofen, Marco; Alvarez, Robert; Hixson, Lucas W

2018-06-01

Radioactive particulate matter (RPM) in St Louis, MO, area surface soils, house dusts and sediments was examined by scanning electron microscopy with energy dispersive X-ray analysis. Analyses found RPM containing 238 U and decay products (up to 46 wt%), and a distinct second form of RPM containing 230 Th and decay products (up to 15.6 wt%). The SEM-EDS analyses found similar RPM in Manhattan Project-era radioactive wastes and indoor dusts in surrounding homes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transport and extraction of radioactive ions stopped in superfluid helium

NARCIS (Netherlands)

Huang, WX; Dendooven, P; Gloos, K; Takahashi, N; Arutyunov, K; Pekola, JP; Aysto, J

A new approach to convert a high energy beam to a low energy one, which is essential for the next generation radioactive ion beam facilities, has been proposed and tested at Jyvaskyla, Finland. An open Ra-223 alpha-decay-recoil source has been used to produce radioactive ions in superfluid helium.

Radioactivity and the French uranium bearing minerals

International Nuclear Information System (INIS)

Guiollard, P.Ch.; Boisson, J.M.; Leydet, J.C.; Meisser, N.

1998-01-01

This special issue of Regne Mineral journal is entirely devoted to the French uranium mining industry. It comprises 4 parts dealing with: the uranium mining industry in France (history, uranium rush, deposits, geologic setting, prosperity and recession, situation in 1998, ore processing); radioactivity and the uranium and its descendants (discovery, first French uranium bearing ores, discovery of radioactivity, radium and other uranium descendants, radium mines, uranium mines, atoms, elements and isotopes, uranium genesis, uranium decay, isotopes in an uranium ore, spontaneous fission, selective migration of radionuclides, radon in mines and houses, radioactivity units, radioprotection standards, new standards and controversies, natural and artificial radioactivity, hazards linked with the handling and collecting of uranium ores, conformability with radioprotection standards, radioactivity of natural uranium minerals); the French uranium bearing minerals (composition, crystal structure, reference, etymology, fluorescence). (J.S.)

Role of shell corrections in the phenomenon of cluster radioactivity

Science.gov (United States)

Kaur, Mandeep; Singh, Bir Bikram; Sharma, Manoj K.

2018-05-01

The detailed investigation has been carried out to explore the role of shell corrections in the decay of various radioactive parent nuclei in trans-lead region, specifically, which lead to doubly magic 208Pb daughter nucleus through emission of clusters such as 14C, 18,20O, 22,24,26Ne, 28,30 Mg and 34S i. The fragmentation potential comprises of binding energies (BE), Coulomb potential (Vc) and nuclear or proximity potential (VP) of the decaying fragments (or clusters). It is relevant to mention here that the contributions of VLDM (T=0) and δU (T=0) in the BE have been analysed within the Strutinsky renormanlization procedure. In the framework of quantum mechanical fragmentation theory (QMFT), we have investigated the above mentioned cluster decays with and without inclusion of shell corrections in the fragmentation potential for spherical as well as non-compact oriented nuclei. We find that the experimentally observed clusters 14C, 18,20O, 22,24,26 Ne, 28,30 Mg and 34Si having doubly magic 208 Pb daughter nucleus are not strongly minimized, they do so only after the inclusion of shell corrections in the fragmentation potential. The nuclear structure information carried by the shell corrections have been explored via these calculations, within the collective clusterisation process of QMFT, in the study of ground state decay of radioactive nuclei. The role of different parts of fragmentation potentials such as VLDM, δU, Vc and Vp is dually analysed for better understanding of radioactive cluster decay.

Natural and Artificial Radioactivity in Drinking Water in Malaga, Spain

International Nuclear Information System (INIS)

Duenas, C.; Fernandez, M.C.; Gordo, E.; Canete, S.; Perez, M.

2011-01-01

Water has a vast importance for numerous human activities, so that securing supplies of drinking water of a standard quality is becoming more and more difficult. The measurement of radioactivity in drinking water permits us to determine the exposure of the population to radiation from the habitual consumption of water. The occurrence of radionuclides in drinking water gives rise to internal exposure of humans, directly on the decay of radionuclides taken into the body through ingestion and inhalation and indirectly when they are incorporated as part of the food-chain The measurement of radioactivity in drinking water permits us to determine the exposure of population to radiation from the habitual consumption of water. An intensive study of the water supply in the city of Malaga during 2002-2010 has been carried out in order to determine the gross alpha activities, gross beta activities and natural and artificial radionuclides present in drinking water. A data base on natural and artificial radioactivity in water was produced. The results indicated that a high percentage of the water sample contains a total gross alpha and beta less than 0.10 Bq/l and 1 Bq/l respectively. The main objectives were: 1) to analyses gross alpha and gross beta activities and to know the statistical distributions. 2) to study the levels of natural and artificial radionuclides 3) to determine a possible mathematical correlation between the radionuclides and several factors.

Automated generation of burnup chain for reactor analysis applications

International Nuclear Information System (INIS)

Tran, Viet-Phu; Tran, Hoai-Nam; Yamamoto, Akio; Endo, Tomohiro

2017-01-01

This paper presents the development of an automated generation of burnup chain for reactor analysis applications. Algorithms are proposed to reevaluate decay modes, branching ratios and effective fission product (FP) cumulative yields of a given list of important FPs taking into account intermediate reactions. A new burnup chain is generated using the updated data sources taken from the JENDL FP decay data file 2011 and Fission yields data file 2011. The new burnup chain is output according to the format for the SRAC code system. Verification has been performed to evaluate the accuracy of the new burnup chain. The results show that the new burnup chain reproduces well the results of a reference one with 193 fission products used in SRAC. Burnup calculations using the new burnup chain have also been performed based on UO_2 and MOX fuel pin cells and compared with a reference chain th2cm6fp193bp6T.

Automated generation of burnup chain for reactor analysis applications

Energy Technology Data Exchange (ETDEWEB)

Tran, Viet-Phu [VINATOM, Hanoi (Viet Nam). Inst. for Nuclear Science and Technology; Tran, Hoai-Nam [Duy Tan Univ., Da Nang (Viet Nam). Inst. of Research and Development; Yamamoto, Akio; Endo, Tomohiro [Nagoya Univ., Nagoya-shi (Japan). Dept. of Materials, Physics and Energy Engineering

2017-05-15

This paper presents the development of an automated generation of burnup chain for reactor analysis applications. Algorithms are proposed to reevaluate decay modes, branching ratios and effective fission product (FP) cumulative yields of a given list of important FPs taking into account intermediate reactions. A new burnup chain is generated using the updated data sources taken from the JENDL FP decay data file 2011 and Fission yields data file 2011. The new burnup chain is output according to the format for the SRAC code system. Verification has been performed to evaluate the accuracy of the new burnup chain. The results show that the new burnup chain reproduces well the results of a reference one with 193 fission products used in SRAC. Burnup calculations using the new burnup chain have also been performed based on UO{sub 2} and MOX fuel pin cells and compared with a reference chain th2cm6fp193bp6T.

Some problems of parametric neutron activation analysis based on the use of radioactive daughters of longer-lived mothers with low mother/daughter half-life ratios

International Nuclear Information System (INIS)

Cohen, I.M.

2012-01-01

The theoretical and practical aspects of the use of radioactive daughters originated from the decay of longer-lived radioactive mothers in parametric activation analysis, when the ratio: mother half-life to daughter half-life is less than 10, are discussed. The mother-daughter relationships: 47 Ca/ 47 Sc; 95 Zr/ 95 Nb; 140 Ba/ 140 La; 99 Mo/ 99m Tc and 115 Cd/ 115m In are selected as models for the study. The cases when the radionuclide of interest is formed through both direct and indirect routes are also analyzed. As illustrative example, the direct reaction and the reaction chain: 47 Ti(n,p) 47 Sc/ 46 Ca(n,γ) 47 Ca(β - ) 47 Sc are evaluated with respect to the determination of the elements involved and their reciprocal interferences. (author)

Radioactive wastes: sources, treatment, and disposal

International Nuclear Information System (INIS)

Wymer, R.G.; Blomeke, J.O.

1975-01-01

Sources, treatment, and disposal of radioactive wastes are analyzed in an attempt to place a consideration of the problem of permanent disposal at the level of established or easily attainable technology. In addition to citing the natural radioactivity present in the biosphere, the radioactive waste generated at each phase of the fuel cycle (mills, fabrication plants, reactors, reprocessing plants) is evaluated. The three treatment processes discussed are preliminary storage to permit decay of the short-lived radioisotopes, solidification of aqueous wastes, and partitioning the long-lived α emitters for separate and long-term storage. Dispersion of radioactive gases to the atmosphere is already being done, and storage in geologically stable structures such as salt mines is under active study. The transmutation of high-level wastes appears feasible in principle, but exceedingly difficult to develop

Radioactive sources in chemical laboratories

International Nuclear Information System (INIS)

Janzekovic, H.; Krizman, M.

2007-01-01

Radioactive sources including all radioactive materials exceeding exemption levels have to be registered in national databases according to international standards based on the recommendations ICRP 60 and a proper licensing should take place as described for example in the 96/29/EURATOM. In spite of that, unregistered sources could be found, usually due to the fact that the owner is not aware of radiation characteristics of sources. The material inventories of chemical laboratories are typical and most frequent example where radioactive sources could be found. Five different types of sources could be identified. The most frequent type are chemicals, namely thorium and uranium compounds. They are used not due to their radioactivity but due to their chemical properties. As for all other sources a stringent control is necessary in order to assure their safe use. Around hundred of stored radioactive chemical items were found during inspections of such laboratories performed by the Slovenian Nuclear Safety Administration or qualified experts in a period December 2006 - July 2007. Users of such chemicals are usually not aware that thorium and uranium chemicals are radioactive and, as unsealed sources, they could be easily spilled out and produce contamination of persons, surfaces, equipment etc. The external exposure as well as the internal exposure including exposure due to inhalation could be present. No knowledge about special precautions is usually present in laboratories and leads to underestimating of a potential risk and unintentional exposure of the laboratory personnel, students etc. Due to the long decay times in decay series of Th -232, U-238 and U- 235 the materials are also radioactive today. Even more, in case of thorium chemicals the radioactivity increased substantially from the time of their production. The implementation of safety measures has been under way and includes a survey of the qualified experts, establishment of organizational structure in a

Fertilizer consumption in Norway and the natural radioactivity in the raw materials

International Nuclear Information System (INIS)

Ormberg, S.

1988-01-01

The principal radionuclides contained in fertilizers are various members of the uranium and thorium decay series and K-40. The radionuclides from the uranium and thorium decay series originate mainly from the phosphorus component of fertilizers, whereas the K-40 originates from the potash component. This paper discusses the radioactivity content of fertilizers used in the Norwegian market and the radioactivity uptake through crops from the use of fertilizers in Norway. It is emphasized that the natural balance of potash in the environment is very little influenced by fertilizers

Production and Evaluation of 236gNp and Reference Materials for Naturally Occurring Radioactive Materials

Science.gov (United States)

Larijani, Cyrus Kouroush

This thesis is based on the development of a radiochemical separation scheme capable of separating both 236gNp and 236Pu from a uranium target of natural isotopic composition ( 1 g uranium) and 200 MBq of fission decay products. The isobaric distribution of fission residues produced following the bombardment of a natural uranium target with a beam of 25 MeV protons has been evaluated. Decay analysis of thirteen isobarically distinct fission residues were carried out using high-resolution gamma-ray spectrometry at the UK National Physical Laboratory. Stoichiometric abundances were calculated via the determination of absolute activity concentrations associated with the longest-lived members of each isobaric chain. This technique was validated by computational modelling of likely sequential decay processes through an isobaric decay chain. The results were largely in agreement with previously published values for neutron bombardments on natural uranium at energies of 14 MeV. Higher relative yields of products with mass numbers A 110-130 were found, consistent with the increasing yield of these radionuclides as the bombarding energy is increased. Using literature values for the production cross-section for fusion of protons with uranium targets, it is estimated that an upper limit of approximately 250 Bq of activity from the 236Np ground state was produced in this experiment. Using a radiochemical separation scheme, Np and Pu fractions were separated from the produced fission decay products, with analyses of the target-based final reaction products made using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and high-resolution alpha and gamma-ray spectrometry. In a separate research theme, reliable measurement of Naturally Occurring Radioactive Materials is of significance in order to comply with environmental regulations and for radiological protection purposes. The thesis describes the standardisation of three reference materials, namely Sand, Tuff and TiO2 which

Superheavy elements and decay properties

Indian Academy of Sciences (India)

chains from 294118 and, it can be seen that our predictions on the α decay ... The Coulomb and proximity potential model for deformed nuclei (CPPMDN) .... Here the half-life is in seconds, Q-value is in MeV and Z is the atomic number of the.

World ocean and radioactive wastes

International Nuclear Information System (INIS)

Kiknadze, O.E.; Sivintsev, Yu.V.

2000-01-01

The radioecological situation that took shape in the Arctic, North Atlantic Ocean and Far East regions as a result of radioactive waste marine disposal was assessed. Accurate account of radionuclides formation and decay in submerged water-water reactors of nuclear submarines suggests that total activity of radioactive waste disposed near the Novaya Zemlya amounted to 107 kCi by the end of 1999. Activity of radioactive waste disposed in the North Atlantic currently is not in excess of 430 kCi. It is pointed out that the Far East region heads the list in terms of total activity disposed (529 kCi). Effective individual dose for critical groups of population in the Arctic, North Atlantic and Far East regions was determined. The conclusion was made that there is no detrimental effect of the radioactive waste disposed on radioecological situation in the relevant areas [ru

Mechanism of f-decay - spontaneous emission of fragments by heavy nuclei

International Nuclear Information System (INIS)

Rubchenya, V.A.; Ehjsmont, V.P.; Yavshits, S.G.

1987-01-01

A new type of model of radioactive decay - spontaneous emission of fragments by heavy nuclei, for which f-decay has been suggested, is formulated. The consideration is based on representation about a disintegrating configuration, for which the probability of f-cluster formation is close to 1. The moments method is used to determine the parameters of the disintegrating configuration. The probability of disintegrating configuration formation is determined by collective properties of a disintegrating nucleus. Effect of nucleon shells of the daughter nucleus and fragment leads to more compact disintegrating configuration and to decay energy increase, that's why at f-decay magic nuclei are formed. Probable spontaneous f-decay values calculated agree satisfactorily with experimental data. The calculational results testify to considerable decrease of f-decay probability at Z≥94

Radioactive waste management from nuclear facilities

International Nuclear Information System (INIS)

2005-06-01

This report has been published as a NSA (Nuclear Systems Association, Japan) commentary series, No. 13, and documents the present status on management of radioactive wastes produced from nuclear facilities in Japan and other countries as well. Risks for radiation accidents coming from radioactive waste disposal and storage together with risks for reactor accidents from nuclear power plants are now causing public anxiety. This commentary concerns among all high-level radioactive waste management from nuclear fuel cycle facilities, with including radioactive wastes from research institutes or hospitals. Also included is wastes produced from reactor decommissioning. For low-level radioactive wastes, the wastes is reduced in volume, solidified, and removed to the sites of storage depending on their radioactivities. For high-level radioactive wastes, some ten thousand years must be necessary before the radioactivity decays to the natural level and protection against seismic or volcanic activities, and terrorist attacks is unavoidable for final disposals. This inevitably results in underground disposal at least 300 m below the ground. Various proposals for the disposal and management for this and their evaluation techniques are described in the present document. (S. Ohno)

Graphical representation of transmutation and decay chain data, transmutation cross section and delayed gamma ray emission data

International Nuclear Information System (INIS)

Seki, Yasushi; Iida, Hiromasa; Kawasaki, Hiromitsu.

1982-09-01

In a D-T burning fusion reactor, the neutron induced activity severely limits personnel access to the reactor. Accurate evaluation of the induced activity and dose rate is necessary to conduct effective biological shield design. In order to evaluate the dose rate accurately, considerable amount of activation data is required. This report gives graphical representation of transmutation and decay chain data, transmutation cross section data and delayed gamma ray emission data for 116 nuclides of interest in terms of fusion reactor design. This graphical representation was made with hope of producing a reference for examining activation problems. It has already been shown to be effective in correcting inappropriate data. A computer code AMOEBA developed for the checking and plotting of the activation data is also described in this report. (author)

Did you know, … Amazing facts on radioactivity and waste disposal

International Nuclear Information System (INIS)

2013-05-01

This brochure published by the Swiss National Cooperative for the Disposal of Radioactive Waste (NAGRA) provides some interesting information on several themes regarding radioactivity. Under the title of ‘Did you know that…’ various lesser-known facts on radioactivity are examined. These include information on radiation emitted by men and women, radioactive radon in buildings as well as the use of radiation to make pepper and spices non-perishable. Also, the use of radioactivity in medicine is discussed. Radioactivity in the earth’s core as the source of geothermal energy is also looked at, as is radioactivity in rock. Also, rock as a material used to screen ionizing radiation sources such as radioactive wastes is discussed. Finally, the time scales involved in radioactive decay are discussed

Lower fungi and radioactivity

International Nuclear Information System (INIS)

Adamek, M.

1989-01-01

Sorption activities for radioactive elements were observed in molds Penicillinum muszynsky, Aspergillus versicolor and Alternaria tenius. Aspergillus flavus, Aspergillus fumigatus and Aspergillus niger were isolated in laboratory and cultivated on a modified substrate containing uranyl nitrate and uranyl acetate. They were found to be capable of absorbing in the biomass some members of the uranium decay series. (E.J.). 4 tabs., 11 refs

Radioactive waste disposal process geological structure for the waste disposal

International Nuclear Information System (INIS)

Courtois, G.; Jaouen, C.

1983-01-01

The process described here consists to carry out the two phases of storage operation (intermediate and definitive) of radioactive wastes (especially the vitrified ones) in a geological dispositif (horizontal shafts) at an adequate deepness but suitable for a natural convection ventilation with fresh air from the land surface and moved only with the calorific heat released by the burried radioactive wastes when the radioactive decay has reached the adequate level, the shafts are totally and definitely occluded [fr

Scalar mesons and radiative vector meson decays

International Nuclear Information System (INIS)

Gokalp, A.; Ylmaz, O

2002-01-01

The light scalar mesons with vacuum quantum numbers J p =0 ++ have fundamental importance in understanding low energy QCD phenomenology and the symmetry breaking mechanisms in QCD. The nature and quark substructure of the best known scalar mesons, isoscalar σ(500), f0(980) and isovector a0(980) have been a subject of continuous controversy. The radioactive decay of neutral vector mesons ρ, w and φ into a single photon and a pair of neutral pseudoscalar mesons have been studied in order to obtain information on the nature of these scalar mesons. For such studies, it is essential that a reliable understanding of the mechanisms for these decays should be at hand. In this work, we investigate the particularly interesting mechanism of the exchange of scalar mesons for the radiative vector meson decays by analysing the experimental results such as measured decay rates and invariant mass spectra and compare them with the theoretical prediction of different reaction mechanisms

Decommissioning Strategies Selection for Facilities Using Radioactive Material

International Nuclear Information System (INIS)

Husen Zamroni; Jaka Rachmadetin

2008-01-01

The facilities using radioactive material that have been stopped operation will require some form of the decommissioning for public and environment safety. The approaches are identified by three decommissioning strategies: immediate dismantling, deferred dismantling and entombment. If a facility undergoes immediate dismantling, most radio nuclides will have no such sufficient time to decay and therefore this strategy may not provide reduction in the worker exposure. A facility that undergoes deferred dismantling may advantage from the radioactive decay of residual radio nuclides during the long term storage period and entombment could be a viable option for other nuclear facilities containing only short lived or limited concentrations of long lived radionuclides. Mostly, only two types of the decommissioning used to be done in the world, immediate and deferred dismantling. (author)

Radioactivity in the hydrologic environment

International Nuclear Information System (INIS)

Werner, L.B.

1969-01-01

Certain proposed uses of nuclear explosives for peaceful purposes will introduce radioactive debris into the natural hydrologic environment. Consideration must therefore be given in each situation to the extent and significance to man of resulting radioactively contaminated water. For contained underground detonations, space-time - concentration predictions of radioactive materials in ground water are dependent on several factors: radionuclide production and initial distribution, radioactive decay, sorption on geologic materials, and dispersion during hydrologic transport. For uncontained (cratering) detonations, other aspects of the hydrologic cycle, particularly rainfall, and watershed characteristics must be considered. Programs sponsored principally by the U.S. Atomic Energy Commission have investigated these factors. Examination of their net effects on radioactivity concentration in water shows that areas if any, underlain by water exceeding permissible concentrations tend first to increase in size, then decrease, and finally disappear. Hydrologic processes at the surface remove or redistribute radioactive debris deposited on a watershed to other locations. Where sufficient information is available, predictions of location and concentration of radionuclides in natural waters can be made. Any potentially hazardous conditions arising from a particular detonation can then be evaluated. (author)

Radioactivity in the hydrologic environment

Energy Technology Data Exchange (ETDEWEB)

Werner, L B [Isotopes, Inc., Palo Alto, CA (United States)

1969-07-01

Certain proposed uses of nuclear explosives for peaceful purposes will introduce radioactive debris into the natural hydrologic environment. Consideration must therefore be given in each situation to the extent and significance to man of resulting radioactively contaminated water. For contained underground detonations, space-time - concentration predictions of radioactive materials in ground water are dependent on several factors: radionuclide production and initial distribution, radioactive decay, sorption on geologic materials, and dispersion during hydrologic transport. For uncontained (cratering) detonations, other aspects of the hydrologic cycle, particularly rainfall, and watershed characteristics must be considered. Programs sponsored principally by the U.S. Atomic Energy Commission have investigated these factors. Examination of their net effects on radioactivity concentration in water shows that areas if any, underlain by water exceeding permissible concentrations tend first to increase in size, then decrease, and finally disappear. Hydrologic processes at the surface remove or redistribute radioactive debris deposited on a watershed to other locations. Where sufficient information is available, predictions of location and concentration of radionuclides in natural waters can be made. Any potentially hazardous conditions arising from a particular detonation can then be evaluated. (author)

Folding model analysis of alpha radioactivity

International Nuclear Information System (INIS)

Basu, D N

2003-01-01

Radioactive decay of nuclei via emission of α-particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the α-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the α nucleus and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction has been used for calculating the nuclear interaction potential which has been supplemented by a zero-range pseudo-potential for exchange along with the density dependence. The nuclear microscopic α-nucleus potential thus obtained has been used along with the Coulomb interaction potential to calculate the action integral within the WKB approximation. This subsequently yields calculations for the half-lives of α decays of nuclei. The density dependence and the exchange effects have not been found to be very significant. These calculations provide reasonable estimates for the lifetimes of α-radioactivity of nuclei

RADFOOD--a dynamic model for radioactivity transfer through the human food chain

International Nuclear Information System (INIS)

Koch, J.; Tadmor, J.

1986-01-01

Radioactive fallout presents a short-term risk due to its direct deposition on agricultural crops, as well as a long-term risk resulting from its deposition on soil and subsequent uptake by crops. A dynamic model, RADFOOD, was developed, based on different existing models. It simulates transport of fallout radionuclides through agricultural food chains to man and evaluates the radiation doses resulting from consumption of contaminated food. Transport was modeled through compartments representing various environmental elements of food products. Internal radiation doses (whole-body weighted doses) following ingestion of contaminated foodstuffs were then estimated. Specific types of crops, soils and diet of man and livestock were considered. A sample calculation was performed in which individual and collective radiation doses, as well as associated health effects, resulting from fallout contamination were evaluated. They were estimated for food consumption beginning at various times after the fallout deposition and for different consumption durations. A sensitivity analysis, performed for the main model parameters, showed that the radiation dose is sensitive, for the short-term period, to changes in initial deposition levels and in the parameters characterizing initial fallout interception and resuspension

Spectrometry techniques for radioactivity measurements

International Nuclear Information System (INIS)

Anilkumar, S.

2016-01-01

The energy of the radiation emission following the nuclear decay is unique and the characteristic of the radio nuclide which undergoes decay. Thus measurement of the energy of the radiation offers a method of identifying the radio nuclides. The prime requirement of the energy measurement is a suitable detector which shows response proportional to the energy of the radiation rather than the presence of the radiation. The response from such detectors are suitably processed and distributed with respect to the signal strength which is proportional to incident energy. This distribution is normally referred as energy spectrum and is recorded in the multichannel analyser. The measurement of energy and intensity of radiation from the spectrum is called radiation spectrometry. Thus the radiation spectrometry allows the identification and quantification of radioactive isotopes in variety of matrices. The radiation spectrometry has now become a popular radioanalytical technique in wide area of nuclear fuel cycle programs. The popular spectrometry techniques commonly used for the radioactivity measurement and analysis are Alpha spectrometry, Gamma ray spectrometry and Beta spectrometry

The management of radioactive waste

International Nuclear Information System (INIS)

1991-08-01

One of the key questions asked about nuclear power production is whether the industry can manage its waste safely and economically. Management must take account of long term safety, since some radioisotopes take a very long time to decay. This long term decay, which can take millions of years, focused attention for the first time on the need for some wastes to be managed for a very long time beyond the lifetime of those who generated the waste. This paper reviews what the different types of waste are, what the technical consensus is on the requirements for their safe management, and how the present state of knowledge developed. It describes how radioactive waste management is practised and planned within the fuel cycle and indicates the moderate scale of the costs in relation to the total cost of producing electricity. Country annexes give more information about what is being done in a selection of countries, in order to indicate how radioactive waste management is carried out in practice. (Author)

Radioactivity and deep geothermal energy; Radioaktivitaet und tiefe Geothermie

Energy Technology Data Exchange (ETDEWEB)

Janczik, Sebastian; Kaltschmitt, Martin [Technische Univ. Hamburg-Harburg (Germany). Inst. fuer Umwelttechnik und Energiewirtschaft; Merkel, Broder [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Geologie

2012-02-15

Due to recent developments in energy politics renewable energies get more and more importance in Germany. This is especially true for geothermal energy representing a promising option for the environmentally sound and secure generation of heat and electricity. But there are a lot of very emotional discussions due to radioactive residues and wastes produced by a geothermal plant. Thus this paper compares radioactivity resulting from geothermal energy with radioactivity coming from other natural sources. In doing so it becomes obvious that naturally radioactive sources exist in all parts of the ecosphere (i.e. air, water, soil). The paper shows also that the specific activities of radioactive elements from geothermal energy in form of residues and waste emerge from radioactive decay of nuclides and that their radiation is not higher than the radiation of other naturally occurring radioactive elements. (orig.)

Radioactive waste gas processing systems

International Nuclear Information System (INIS)

Kita, Kaoru; Minemoto, Masaki; Takezawa, Kazuaki.

1981-01-01

Purpose: To effectively separate and remove only hydrogen from hydrogen gas-containing radioactive waste gases produced from nuclear power plants without using large scaled facilities. Constitution: From hydrogen gas-enriched waste gases which contain radioactive rare gases (Kr, Xe) sent from the volume control tank of a chemical volume control system, only the hydrogen is separated in a hydrogen separator using palladium alloy membrane and rare gases are concentrated, volume-decreased and then stored. In this case, an activated carbon adsorption device is connected at its inlet to the radioactive gas outlet of the hydrogen separator and opened at its outlet to external atmosphere. In this system, while only the hydrogen gas permeates through the palladium alloy membrane, other gases are introduced, without permeation, into the activated carbon adsorption device. Then, the radioactive rare gases are decayed by the adsorption on the activated carbon and then released to the external atmosphere. (Furukawa, Y.)

The stakes in managing radioactive wastes

International Nuclear Information System (INIS)

Boissier, F.

2012-01-01

Like any human activity, the nuclear industry produces wastes. The wastes containing radioactive substances have to be managed as a function of the related risks. Nowadays, 1.300.000 tons of radioactive wastes have accumulated in France. More than 90% of them have short half-lives and are stored on the ground by ANDRA (national agency for the management of radioactive wastes) on 2 sites in the Aube district. ANDRA also designs solutions for stocking the other wastes. Those with long half-lives and very high activity will be stored deep underground (500 meter deep) at Cigeo in the Meuse and Haute-Marne districts. The wastes with long half-lives but low activity (less than 10 5 decays/s for graphite and less than a few thousands decays/s for radium contaminated wastes) will be disposed in a specific way. Implementing a storage solution for each type of waste is necessary for the nuclear industry's sustainability, but it does not dispense the latter from pursuing its efforts to reduce the quantity and danger of the wastes produced. This holds in particular for the so-called 'fourth generation' of future installations. It is important to take stock of all the issues related to managing nuclear wastes

Extremely long-lived magnetic excitations in supported Fe chains

Science.gov (United States)

Gauyacq, J. P.; Lorente, N.

2016-07-01

We report on a theoretical study of the lifetime of the first excited state of spin chains made of an odd number of Fe atoms on C u2N /Cu (100 ) . Yan, Choi, Burgess, Rolf-Pissarczyk, and Loth [Nat. Nanotech. 10, 40 (2015), 10.1038/nnano.2014.281] recently observed very long lifetimes in the case of F e3 chains. We consider the decay of the first excited state induced by electron-hole pair creation in the substrate. For a finite magnetic field, the two lowest-lying states in the chain have a quasi-Néel state structure. Decay from one state to the other strongly depends on the degree of entanglement of the local spins in the chain. The weak entanglement in the chain accounts for the long lifetimes that increase exponentially with chain length. Despite their apparently very different properties, the behavior of odd and even chains is governed by the same kind of phenomena, in particular entanglement effects. The present results account quite well for the lifetimes recently measured by Yan et al. on F e3 .

ZZ RADDECAY, Decay Data Library for Radiological Assessment

International Nuclear Information System (INIS)

2000-01-01

Description of program or function: - Format: special format defined in documentation. - Nuclides: 500 nuclides of interest in the nuclear fuel cycle, environmental problems, nuclear medicine, fusion reactor technology, and radiological protection assessment. - Origin: DLC-80/DRALIST. ZZ-RADDECAY is a data library of half-lives, radioactive daughter nuclides, probabilities per decay and decay product energies for alpha particles, positrons, electrons, X-rays, and gamma-rays. The current data base contains approximately 500 nuclides of interest in the nuclear fuel cycle, environmental problems, nuclear medicine, fusion reactor technology, and radiological protection assessment. RADIATION DECAY VERSION 2 March 1997: This application is being provided by Aptec as 'Freeware' with permission of the author Mr. Charles Hacker, Engineering and Applied Science, Griffith University, Australia

Determination of radioactivity levels from some Egyptian building materials

International Nuclear Information System (INIS)

Abd EL Sattar, M.; Morsy, A.A.

2007-01-01

Our world is radioactive and has been, since it was created. Over 60 radionuclides (radioactive elements) can be found in nature. Radon is naturally occurring radioactive gas, that is produced by the radioactive decay of radium. Breathing high concentration of radon can cause lung cancer. A set of experiments were carried out using Cr-39 as solid state nuclear track detectors with the optimum etching conditions, 6.25 N Na OH at 70 o C for 8 hours. The radon-222 activity in this survey was found to be in the range of 0.303 kBq/m 3 to 5.04 KBq/m 3 for different building materials in Egypt

Rapid heating tensile tests of high-energy-rate-forged 316L stainless steel containing internal helium from radioactive decay of absorbed tritium

International Nuclear Information System (INIS)

Mosley, W.C.

1990-01-01

316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. This austenitic stainless steel is frequently used in the high-energy-rate-forged (HERF) metallurgical condition to take advantage of increased strength produced by cold work introduced by this process. Proper design of tritium-handling equipment will require an understanding of how helium-3, the product of radioactive decay of tritium, affects mechanical properties. This report describes results of elevated-temperature tensile testing of HERF 316L stainless steel specimens containing helium concentrations of 171 (calculated) atomic parts per million (appm). Results are compared with those reported previously for specimens containing 0 and 94 (measured) appm helium

Quantitative performance allocation of multi-barrier system for high-level radioactive waste disposal

International Nuclear Information System (INIS)

Ahn, Joon-Hong; Ikeda, Takao; Ohe, Toshiaki

1995-01-01

Performance assessment of each barrier consisting of geologic disposal system for high-level radioactive wastes is carried out quantitatively, and key radionuclides and parameters are pointed out. Chemical compositions and solubilities of radionuclides under repository conditions are determined by PHREEQE code staring from compositions of granitic groundwater observed in Japan. Glass dissolution analysis based on mass transfer theory and precipitation analysis have been done in order to determine the inner boundary condition for radionuclide diffusion through a bentonite-filled buffer region, where multi-member decay chain and isotopic sharing of solubility at the inner boundary are considered. Natural barrier is treated as homogeneous porous rock, or porous rock with infinite planar fractures. Performance of each barrier is evaluated in terms of non-dimensionalized hazard defined as the ratio of annual radioactivity release from each barrier to the annual limit on intake. At the outer edge of the engineered barriers, 239 Pu is the key unclide to the performance, whereas at the exit of the natural barrier, weakly-sorbing fission product nuclides such as 135 Cs, 129 I and 99 Tc dominate the hazard. (author) 50 refs

Measurement of radioactivity in water samples

International Nuclear Information System (INIS)

Richards, L.

1990-01-01

Public concern about the levels of radioactivity release to the environment whether authorised discharges or resulting from nuclear accident, has increased in recent years. Consequently there is increasing pressure for reliable data on the distribution of radioactivity and the extent of its intrusion into food chains and water supplies. As a result a number of laboratories not experienced in radioactivity measurements have acquired nucleonic counting equipment. These notes explore the underlying basics and indicate sources of essential data and information which are required for a better understanding of radioactivity measurements. Particular attention is directed to the screening tests which are usually designated ''gross'' alpha and ''gross'' beta activity measurement. (author)

2He decay from excited states: the 18Ne case

International Nuclear Information System (INIS)

Raciti, G.; Sfienti, C.; De Napoli, M.; Rapisarda, E.; Cardella, G.; Giacoppo, F.

2011-01-01

Two-proton radioactivity studies have been performed on excited states of 18 Ne produced by 20 Ne fragmentation at the FRIBs facility of the Laboratori Nazionali del Sud. The study of the relative-momentum correlations of the two protons allowed to disentangle the diproton, democratic and sequential decay contributions to the 2p emission. In order to extend the study on two-proton decay to other light-masses nuclei, an upgrade of the FRIBs facility is planned. A new configuration of the Fragment Separator would be able to increase the acceptance of the beam line and therefore the yield of the produced radioactive beams. Also the present tagging setup will be modified in view of the gain intensity, in order to sustain the higher foreseen incoming rate. Status and perspectives of the facility will be presented. (author)

MASCOT user's guide--Version 2.0: Analytical solutions for multidimensional transport of a four-member radionuclide decay chain in ground water

International Nuclear Information System (INIS)

Gureghian, A.B.

1988-07-01

The MASCOT code computes the two- and three-dimensional space-time dependent convective-dispersive transport of a four-member radionuclide decay chain in unbounded homogeneous porous media, for constant and radionuclide-dependent release, and assuming steady- state isothermal ground-water flow and parallel streamlines. The model can handle a single or multiple finite line source or a Gaussian distributed source in the two-dimensional case, and a single or multiple patch source or bivariate-normal distributed source in the three-dimensional case. The differential equations are solved by Laplace and Fourier transforms and a Gauss-Legendre integration scheme. 33 figs., 3 tabs

Disposal of liquid radioactive waste - discharge of radioactive waste waters from hospitals

International Nuclear Information System (INIS)

Ludwieg, F.

1976-01-01

A survey is given about legal prescriptions in the FRG concerning composition and amount of the liquid waste substances and waste water disposal by emitting into the sewerage, waste water decay systems and collecting and storage of patients excretions. The radiation exposure of the population due to drainage of radioactive waste water from hospitals lower by more than two orders than the mean exposure due to nuclear-medical use. (HP) [de

Radioactivity, radionuclides, radiation

CERN Document Server

Magill, Joseph

2005-01-01

RADIOACTIVITY – RADIONUCLIDES – RADIATION is suitable for a general audience interested in topical environmental and human health radiological issues such as radiation exposure in aircraft, food sterilisation, nuclear medicine, radon gas, radiation dispersion devices ("dirty bombs")… It leads the interested reader through the three Rs of nuclear science, to the forefront of research and developments in the field. The book is also suitable for students and professionals in the related disciplines of nuclear and radiochemistry, health physics, environmental sciences, nuclear and astrophysics. Recent developments in the areas of exotic decay modes (bound beta decay of ‘bare’ or fully ionized nuclei), laser transmutation, nuclear forensics, radiation hormesis and the LNT hypothesis are covered. Atomic mass data for over 3000 nuclides from the most recent (2003) evaluation are included.

Measurement of artificial radioactivity in the atmosphere at Ottawa, Canada

Energy Technology Data Exchange (ETDEWEB)

Terentiuk, F

1958-01-01

In recent years there has been considerable interest in the artificial radioactivity in the atmosphere originating from atomic and thermonuclear explosions. For the past year daily measurements of radioactivity have been made at Ottawa. The sampling times corresponded to air volumes of 425 cubic metric and 2000 cubic meters, respectively. Filters were kept for a period of 3 days before measurements were made in order to permit natural activity resulting from daughter products of radon and thoron to decay to a negligible value. Measurements of the gross beta activity from the filters were made directly with end-window Geiger tubes. Filters showing considerable initial radioactivity were measured at intervals of a few days in order to obtain the rate of decay of the activity. It was hoped that the data obtained would make it possible to fix the date of the explosion responsible for the filter activity but the fixing of dates was very uncertain.

Characterization of uranium in bituminized radioactive waste drums by self-induced X-ray fluorescence

International Nuclear Information System (INIS)

Pin, Patrick; Perot, Bertrand

2013-06-01

This paper reports the experimental qualification of an original uranium characterization method based on fluorescence X rays induced by the spontaneous gamma emission of bituminized radioactive waste drums. The main 661.7 keV gamma ray following the 137 Cs decay produces by Compton scattering in the bituminized matrix an intense photon continuum around 100 keV, i.e. in the uranium X-ray fluorescence region. 'Self-induced' X-rays produced without using an external source allow a quantitative assessment of uranium as 137 Cs and uranium are homogeneously mixed and distributed in the bituminized matrix. The paper presents the experimental qualification of the method with real waste drums, showing a detection limit well below 1 kg of uranium in 20 min acquisitions while the usual gamma rays of 235 U (185 keV) or 238 U (1001 keV of 234m Pa in the radioactive decay chain) are not detected. The relative uncertainty on the uranium mass assessed by self-induced X-ray fluorescence (SXRF) is about 50%, with a 95% confidence level, taking into account the correction of photon attenuation in the waste matrix. This last indeed contains high atomic numbers elements like uranium, but also barium, in quantities which are not known for each drum. Attenuation is estimated thanks to the peak-to-Compton ratio to limit the corresponding uncertainty. The SXRF uranium masses measured in the real drums are in good agreement with long gamma-ray spectroscopy measurements (1001 keV peak) or with radiochemical analyses. (authors)

Biosynthesis of triacylglycerols containing very long chain monounsaturated acyl moieties in developing seeds

International Nuclear Information System (INIS)

Fehling, E.; Murphy, D.J.; Mukherjee, K.D.

1990-01-01

Particulate (15,000g) fractions from developing seeds of honesty (Lunaria annua L.) and mustard (Sinapis alba L.) synthesize radioactive very long chain monounsaturated fatty acids (gadoleic, erucic, and nervonic) from [1- 14 C]oleoyl-CoA and malonyl-CoA or from oleoyl-CoA and [2- 14 C]malonyl-CoA. The very long chain monounsaturated fatty acids are rapidly channeled to triacylglycerols and other acyl lipids without intermediate accumulation of their CoA thioesters. When [1- 14 C]oleoyl-CoA is used as the radioactive substrate, phosphatidylcholines and other phospholipids are most extensively radiolabeled by oleoyl moieties rather than by very long chain monounsaturated acyl moieties. When [2- 14 C]malonyl-CoA is used as the radioactive substrate, no radioactive oleic acid is formed and the newly synthesized very long chain monounsaturated fatty acids are extensively incorporated into phosphatidylcholines and other phospholipids as well as triacylglycerols. The pattern of labeling of the key intermediates of the Kennedy pathway, e.g. lysophosphatidic acids, phosphatidic acids, and diacylglycerols by the newly synthesized very long chain monounsaturated fatty acids is consistent with the operation of this pathway in the biosynthesis of triacylglycerols

Compilations and evaluations of nuclear structure and decay data

International Nuclear Information System (INIS)

Lorenz, A.

1977-03-01

This is the second issue of a report series on published and to-be-published compilations and evaluations of nuclear structure and decay (NSD) data. This compilation of compilations and evaluations is designed to keep the nuclear scientific community informed of the availability of compiled or evaluated NSD data, and contains references to laboratory reports, journal articles and books containing selected compilations and evaluations. It excludes references to ''mass-chain'' evaluations normally published in the ''Nuclear Data Sheets'' and ''Nuclear Physics''. The material contained in this compilation is sorted according to eight subject categories: general compilations; basic isotopic properties; nuclear structure properties; nuclear decay processes; half-lives, energies and spectra; nuclear decay processes: gamma-rays; nuclear decay processes: fission products; nuclear decay processes: (others); atomic processes

Decay Heat Calculations for Reactors: Development of a Computer Code ADWITA

International Nuclear Information System (INIS)

Raj, Devesh

2015-01-01

Estimation of release of energy (decay heat) over an extended period of time after termination of neutron induced fission is necessary for determining the heat removal requirements when the reactor is shutdown, and for fuel storage and transport facilities as well as for accident studies. A Fuel Cycle Analysis Code, ADWITA (Activation, Decay, Waste Incineration and Transmutation Analysis) which can generate inventory based on irradiation history and calculate radioactivity and decay heat for extended period of cooling, has been written. The method and data involved in Fuel Cycle Analysis Code ADWITA and some results obtained shall also be presented. (author)

Treatment of short-lived radioactive wastes

International Nuclear Information System (INIS)

Yamaguchi, Chiri

1976-01-01

Recently short life nuclides have come to be utilized increasingly as diagnostic radioisotopes, and Tc-99m (half-life; 6.05 hours) and Ga-67 (half-life 7.79 hours) are replacing the most nuclides fomerly used in vivo test. Such development of radioactive products inevitably causes the rapid increase of their wastes. At present, the radioactive wastes produced by hospitals and university laboratories in Japan are collected by the Japan Radioisotope Association, and treated by the Japan Atomic Energy Research Institute. These wastes are divided into combustibles and incombustibles to store in the store house in the Japan Atomic Energy Research Institute. The present law in Japan contains the contradiction which treats the matter with one several millionth of radioactivity after decay same as the original radioactive matter. Thus solid must be stored permanently, while gas and liquid can be discharged after dilution. (Kobatake, H.)

Selection of RNA Aptamers Against Botulinum Neurotoxin Type A Light Chain Through a Non-Radioactive Approach.

Science.gov (United States)

Chang, Tzuu-Wang; Janardhanan, Pavithra; Mello, Charlene M; Singh, Bal Ram; Cai, Shuowei

2016-09-01

Botulinum neurotoxin (BoNT), a category A agent, is the most toxic molecule known to mankind. The endopeptidase activity of light chain domain of BoNT is the cause for the inhibition of the neurotransmitter release and the flaccid paralysis that leads to lethality in botulism. Currently, antidotes are not available to reverse the flaccid paralysis caused by BoNT. In the present study, a non-radioactive-based systematic evolution of ligands by exponential enrichment (SELEX) process is developed by utilizing surface plasmon resonance to monitor the binding enrichment. Two RNA aptamers have been identified as strong binders against light chain of botulinum neurotoxin type A. These two aptamers showed strong inhibition activity on LCA, with IC50 in nanomolar range. Inhibition kinetic studies reveal mid nanomolar KI and non-competitive nature of their inhibition, suggesting that they have strong potential as antidotes that can reverse the symptom caused by BoNT/A. More importantly, we observed that the 2'-fluorine-pyrimidine-modified RNA aptamers identified here do not change their binding and biological activities. This observation could lead to a cost-effective way for SELEX, by using regular nucleotide during SELEX, and 2'-fluorine-pyrimidine-modified nucleotide for final application to enhance their RNase-resistance.

Radioactivity of air caused by nuclear bomb tests

Energy Technology Data Exchange (ETDEWEB)

Aron, A; Gross, B

1957-01-01

Daily checks of radioactive fallout at the above institute (Instituto Nacional de Tecnologia, Rio de Janeiro) gave an activity 10 times as high as the average on June 25, 1957. By applying the decay law for fallout of Way and Wigner the origin could be traced to the British H-bomb test at Christmas Island on May 15, 1957. By autoradiography of the filter it was shown that the high activity was caused by only one highly radioactive particle.

Influence of proton-skin thickness on the {{\\alpha }} decays of heavy nuclei

Science.gov (United States)

Seif, W. M.; Abdurrahman, A.

2018-01-01

We investigate the effect of proton-skin thickness on the α decay process. We consider 188 neutron-deficient nuclei belonging to the isotopic chains from Te (Z = 52) to Pb (Z = 82). The calculations of the half-life are carried out in the framework of the preformed cluster model, with the Wentzel-Kramers-Brillouin penetration probability and assault frequency. It is shown that the proton-skin thickness ({\\varDelta }{{p}}) of the daughter nucleus gives rise to a total α- daughter nucleus interaction potential of relatively wide deep internal pocket and a thinner Coulomb barrier of less height. This increases the penetration probability but decreases the assault frequency. The overall impact of the proton-skin thickness appears as a decrease in the decay half-life. The proton-skin thickness decreases the stability of the nucleus. The half-lives of the proton-skinned isotopes along the isotopic chain decrease exponentially with increasing the proton-skin thickness, whereas the {Q}α -value increases with {\\varDelta }{{p}}. α-decay manifests itself as the second favorite decay mode of neutron-deficient nuclei, next to the {β }+-decay and before proton-decay. It is indicated as main, competing, and minor decay mode, at 21%, 7%, and 57%, respectively, of the investigated nuclei.

Final report: Accelerated beta decay for disposal of fission fragment wastes

International Nuclear Information System (INIS)

Reiss, Howard R.

2000-01-01

The fundamental theory of the interaction of intense, low-frequency electromagnetic fields with certain radioactive nuclei has been fully formulated. The nuclei are of the type that exists in high-level radioactive wastes that are end products of the production of energy from nuclear fission. The basic physical mechanisms that underlie the coupling of the applied field to the nucleus have been identified. Both the basic theory and numerical predictions that stem from it support the conclusion that high-level radioactive wastes can be disposed of by substantially accelerating the rate of radioactive decay. Some old experiments on the acceleration of this type of radioactivity, with results that were not understood at the time, have been re-examined. Their interpretation is now clear, and the experiments are found to be in agreement with the theory

Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait.

Science.gov (United States)

Alazemi, N; Bajoga, A D; Bradley, D A; Regan, P H; Shams, H

2016-07-01

An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the (238)U and (232)Th decay chains and (40)K which. The (238)U and (232)Th chain radionuclides and (40)K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of (238)U, (232)Th and (40)K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

A theoretical study of cluster radioactivity in platinum isotopes

Energy Technology Data Exchange (ETDEWEB)

Joseph, Deepthy Maria; Ashok, Nithu; Joseph, Antony [University of Calicut, Department of Physics, Malappuram, Kerala (India)

2018-01-15

The probable cluster decay modes in platinum isotopes are predicted with the help of effective liquid drop model. The calculated half-lives are compared with those of universal decay law model and with the experimental data. The investigation affirms the decisive role of neutron magicity in the phenomenon of cluster radioactivity. It is found that the probability of cluster emission decreases with the increase in the neutron number of parent nucleus. Geiger-Nuttall plots of the probable decay modes show linear behaviour, which in turn leads to the equation for logarithmic half-life for the clusters emitted from Pt isotopes. (orig.)

Transverse intrinsic localized modes in monatomic chain and in graphene

Energy Technology Data Exchange (ETDEWEB)

Hizhnyakov, V. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Klopov, M. [Department of Physics, Faculty of Science, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); Shelkan, A., E-mail: shell@ut.ee [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

2016-03-06

In this paper an analytical and numerical study of anharmonic vibrations of monatomic chain and graphene in transverse (perpendicular) with respect to the chain/plane direction is presented. Due to the lack of odd anharmonicities and presence of hard quartic anharmonicity for displacements in this direction, there may exist localized anharmonic transverse modes with the frequencies above the spectrum of the corresponding phonons. Although these frequencies are in resonance with longitudinal (chain) or in-plane (graphene) phonons, the modes can decay only due to a weak anharmonic process. Therefore the lifetime of these vibrations may be very long. E.g. in the chain, according to our theoretical and numerical calculations it may exceed 10{sup 10} periods. We call these vibrations as transverse intrinsic localized modes. - Highlights: • In a stretched monatomic chain, long-living nonlinear transverse localized modes may exist. • Transverse vibrations of a chain slowly decay due to creation of longitudinal phonons. • Lifetime of transverse vibrations of a chain may exceed billion periods of vibrations. • In stretched graphene, long-living out-of-plain localized vibrations may exist.

Risk considerations for a long-term open-state of the radioactive waste storage facility Schacht Asse II. Variation of the parameter sets for radio-ecological modeling using the Monte Carlo method

International Nuclear Information System (INIS)

Kueppers, Christian; Ustohalova, Veronika

2013-01-01

The risk considerations for a long-term open-state of the radioactive waste storage facility Schacht Asse II include the following issues: description of radio-ecological models for the radionuclide transport in the covering rock formations and determination of the radiation exposure, parameters of the radio-ecological and their variability, Monte-Carlo method application. The results of the modeling calculations include the group short-living radionuclides, long-living radionuclides, radionuclides in the frame of decay chains and sensitivity analyses with respect to the correlation of input data and results.

Development of plastic scintillator based food radioactivity contamination monitoring system

International Nuclear Information System (INIS)

Parihar, A.; Sahani, R.M.; Mahala, V.K.; Vaijapurkar, S.G.

2016-01-01

Radioactivity is naturally present in soil, water and food stuffs. Food can be contaminated after discharge of radioactivity into the environment from industries that concentrate natural radionuclide and from civil or military nuclear operations. The contamination can be in three ways; by direct deposition, through the food chain and induced radioactivity due to exposure of high neutron flux. The health effects on human depend on the type of radionuclide and the length of time people are exposed to it. The studies of fission product behaviour in the food chain have revealed radionuclide Strontium-90, Caesium 137 and Iodine-131 are of major concern. Plastic scintillator is already developed indigenously at Defence Laboratory, Jodhpur. Efforts has been made to develop a portable field instrument using plastic scintillator for assessment of beta ( 90 Sr) and gamma ( 137 Cs and 131 I) radioactivity in food

Radioactive ores from Agostinho field, Pocos de Caldas (MG), Brazil

International Nuclear Information System (INIS)

Fujimori, K.

1974-01-01

Aiming to characterize the radioactive minerals of Campo Agostinho, Pocos de Caldas - Brazil, the survey of all natural radiactive elements and their geochemical behaviors, decays and radioactive equilibrium was done. Several models of radioactive instability of the minerals or the radioactive samples were proposed to characterize the geochemistry and the mineralization of radioactive elements. The complete isotopic analysis of the elements was done by high resolution gamma spectrometry, using a Ge(Li) detector, at the temperature of liquid nitrogen, coupled to a multichannel analyser. The sample in radioactive equilibrium of Atomic Energy Comission of United States - A.S. n.6, NBL - New Brunswick Laboratory, was considered as standard sample. Fluorite, zircons, pirite, molibinite, rutile, anatase, niobophyllite, and in small ratio (bellow 0.1%) uranothorianite, coffinite, pyrochlore, monazite and apatite. (M.C.K.) [pt

Study of the decay 184Hg→184Au (Tsub(1/2)=30s)

International Nuclear Information System (INIS)

Nettles, W.G.; Beraud, R.; Cole, J.D.; Hamilton, J.H.; Ramayya, A.V.; Kawakami, H.; Spejewski, E.H.

1978-01-01

The radioactive decay of 184 Hg to 184 Au was studied on line with the UNISOR isotope separator. The 184 mass chain was entered at 184 Tl and 184 Hg by bombarding an isotopically-enriched target of 180 W with 14 N ions of 177 MeV. Multiscale singles and γ-γ-time coincidence studies were carried out. No previous levels have been assigned to 184 Au. From the coincidence data eight levels at 156.2, 159.1, 247.7, 282.8, 295.1, 392.4, 418.0 and 412.4 keV are assigned and two tentative levels at 534.0 and 551.6 keV are proposed. By using the delayed coincidence technique, a half-life of 36+-6 nanoseconds was measured for the 156.2 keV first-excited level and upper limits of 2 nanoseconds were determined for the half-lives of levels at 159.1, 247.7, 295.1 and 392.4 keV [fr

Source of radioactivity in the ocean environment

International Nuclear Information System (INIS)

Solomon, K.A.

1988-01-01

This paper summarizes both natural and man-made radioactivity in the marine environment. Radioactivity occurs naturally in both the sea water and in the ocean sediment. Radioactivity in the sea water is fairly uniform geographically and is dominated by the naturally occurring isotope 40/K (potassium-40). Unlike sea water, sediment radiation levels vary with sediment type and location. The primary source of natural radiation in the sediment results from deposition of insoluble thorium isotopes formed by the decay of water-soluble uranium. Man-made sources of radioactivity arise from, in descending order of importance: - sinking of two U.S. and two Soviet nuclear submarines; fallout from nuclear weapons testing; dumping of primarily British and Americal low-level nuclear waste; and dumping of reprocessing plant radiated effluents from the British Windscale facility and other European and Indian reprocessing facilities. 1 table

Spin tests for intermediate states in radiative psi'(3684) decay chains

International Nuclear Information System (INIS)

Kabir, P.K.; Hey, A.J.G.

1976-01-01

Analysis of the multiple angular-correlation functions for the sequential decays psi'(1 - ) → γ + chi, chi → M anti M, where M is a spinless meson, and psi'(1 - ) → γ 1 + chi, chi → γ 2 + psi, psi (1 - ) → l anti l, when the psi' is formed in e + e - collisions, shows that these can unambiguously distinguish between the spin assignments s/sub chi/ = 0, 1 or 2 for the intermediate states occurring in these decays, as well as determine the multipole amplitudes contributing to the radiative transitions. No dynamical assumptions are made beyond the conservation of angular momentum and parity; recoils are fully taken into account

An application program for fission product decay heat calculations

International Nuclear Information System (INIS)

Pham, Ngoc Son; Katakura, Jun-ichi

2007-10-01

The precise knowledge of decay heat is one of the most important factors in safety design and operation of nuclear power facilities. Furthermore, decay heat data also play an important role in design of fuel discharges, fuel storage and transport flasks, and in spent fuel management and processing. In this study, a new application program, called DHP (Decay Heat Power program), has been developed for exact decay heat summation calculations, uncertainty analysis, and for determination of the individual contribution of each fission product. The analytical methods were applied in the program without any simplification or approximation, in which all of linear and non-linear decay chains, and 12 decay modes, including ground state and meta-stable states, are automatically identified, and processed by using a decay data library and a fission yield data file, both in ENDF/B-VI format. The window interface of the program is designed with optional properties which is very easy for users to run the code. (author)

Radioactive waste management for a radiologically contaminated hospitalized patient

International Nuclear Information System (INIS)

Pina Jomir, G.; Michel, X.; Lecompte, Y.; Chianea, N.; Cazoulat, A.

2015-01-01

Radioactive waste management in the post-accidental phase following caring for a radiologically contaminated patient in a hospital decontamination facility must be anticipated at a local level to be truly efficient, as the volume of waste could be substantial. This management must comply with the principles set out for radioactive as well as medical waste. The first step involves identification of radiologically contaminated waste based on radioactivity measurement for volume reduction. Then, the management depends on the longest radioactive half-life of contaminative radionuclides. For a half-life inferior to 100 days, wastes are stored for their radioactivity to decay for at least 10 periods before disposal like conventional medical waste. Long-lived radioactive waste management implies treatment of liquid waste and special handling for sorting and packaging before final elimination at the French National Agency for Radioactive Waste Management (ANDRA). Following this, highly specialized waste management skills, financial responsibility issues and detention of non-medical radioactive sources are questions raised by hospital radioactive waste management in the post-accidental phase. (authors)

Natural occurring radioactive substances. Vol. 1

Energy Technology Data Exchange (ETDEWEB)

Emara, A E [National Center for radiation Research and Technology Atomic Energy Authority, Cairo (Egypt)

1996-03-01

Naturally occurring radioactive substances produced by cosmic rays of those of terrestrial origin are surveyed. The different radioactive decay series are discussed. Special emphasis is given to the element radium as regards its properties and distribution in different environmental samples. The properties of naturally occurring k-40 and its distribution in different natural media are also outlined. Induced radionuclides which are formed as a result of the interaction of cosmic rays with the constituents of the atmosphere are mentioned. In this respect the intensity of natural background radiation and the dose at different locations and levels is surveyed. Some regions of exceptionally high radioactivity which result in high exposure rates are mentioned. Monazite deposits and water springs are mentioned in some detail. The Oklo phenomenon as a natural reactor is also discussed. 8 tabs.

Natural occurring radioactive substances. Vol. 1

International Nuclear Information System (INIS)

Emara, A.E.

1996-01-01

Naturally occurring radioactive substances produced by cosmic rays of those of terrestrial origin are surveyed. The different radioactive decay series are discussed. Special emphasis is given to the element radium as regards its properties and distribution in different environmental samples. The properties of naturally occurring k-40 and its distribution in different natural media are also outlined. Induced radionuclides which are formed as a result of the interaction of cosmic rays with the constituents of the atmosphere are mentioned. In this respect the intensity of natural background radiation and the dose at different locations and levels is surveyed. Some regions of exceptionally high radioactivity which result in high exposure rates are mentioned. Monazite deposits and water springs are mentioned in some detail. The Oklo phenomenon as a natural reactor is also discussed. 8 tabs

Surveillance of the radioactivity in the environment of the Loire basin

International Nuclear Information System (INIS)

2008-12-01

The surveillance of the radioactivity in environment in the Loire catchment basin rests on the measurement of radioactivity in atmosphere, in the rain waters and continental waters as well as the follow up of radioactivity in food chain. Concerning the air radiation monitoring, that is the dose rate measurement of ambient gamma radiation, the radon measurement and the measurement of particulates and radioactive aerosols. Concerning the food chain, the follow up is made on drinking water, milk, fishes and the special case of strontium 90. The actors of this campaign are the institute of radiation protection and nuclear safety (I.R.S.N.), Electricite de France (E.D.F.) Areva NC, the associations qualified for the surveillance of air quality (A.A.S.Q.A.) and the government services. (N.C.)

On measuring the masses of pair-produced semi-invisibly decaying particles at hadron colliders

International Nuclear Information System (INIS)

Tovey, Daniel R.

2008-01-01

A straightforward new technique is introduced which enables measurement at hadron colliders of an analytical combination of the masses of pair-produced semi-invisibly decaying particles and their invisible decay products. The new technique makes use of the invariance under contra-linear Lorentz boosts of a simple combination of the transverse momentum components of the aggregate visible products of each decay chain. In the general case where the invariant masses of the visible decay products are non-zero it is shown that in principle the masses of both the initial particles from the hard scattering and the invisible particles produced in the decay chains can be determined independently. This application is likely to be difficult to realise in practice however due to the contamination of the final state with ISR jets. The technique may be of most use for measurements of SUSY particle masses at the LHC, however the technique should be applicable to any class of hadron collider events in which heavy particles of unknown mass are pair-produced and decay to semi-invisible final states

The sorption of 210Pb, 210Bi and 210Po on montmorillonite: a study with emphasis on reversibility aspects and on the effect of the radioactive decay of adsorbed nuclides

International Nuclear Information System (INIS)

Ulrich, H.J.; Degueldre, C.

1993-01-01

The influence of the ionic strength and of pH on the adsorption/desorption processes of Pb, Bi and Po on montmorillonite has been investigated. For Pb, a strong dependence of the adsorption and desorption processes on the ionic strength was observed at pH d ) are measured. They range from 10 3 to 10 5 ml . g -1 for Pb and from 10 4 to 10 7 ml . g -1 for 210 Bi and 210 Po. When adsorption and desorption coefficients are compared, an agreement is found for both adsorption/desorption R d 's of Pb, whereas, for Bi and Po adsorption R d 's were several orders of magnitude lower than those obtained for desorption. The chemical activities of free Bi and Po in the liquid phase are limited by the formation of Bi and Po-colloids prior to the sorption step. This fact could explain the differences in the R d values. While the adsorption of Pb was reversible, only very small amounts of BI and Po could be desorbed from the montmorillonite (quasi-irreversible adsorption). The radioactive decay of adsorbed 210 Pb to 210 Bi, which in turn decays to 210 Po, can lead to significant changes in the desorption behaviour of the daughter nuclides. Whereas the sorption is nearly irreversible if Bi and Po adsorb on montmorillonite from the aqueous phase, they desorb more easily if they are generated by the radioactive decay of adsorbed 210 Pb. The difference in the distribution coefficients R d is approximately one order of magnitude in the case of Po, and more than 2 orders of magnitude in the case of Bi. (orig.)

Radioactive gas waste processing device

International Nuclear Information System (INIS)

Soma, Koichi.

1996-01-01

The present invention concerns a radioactive gas waste processing device which extracts exhaust gases from a turbine condensator in a BWR type reactor and releases them after decaying radioactivity thereof during temporary storage. The turbine condensator is connected with an extracting ejector, a preheater, a recombiner for converting hydrogen gas into steams, an off gas condensator for removing water content, a flow rate control valve, a dehumidifier, a hold up device for removing radiation contaminated materials, a vacuum pump for sucking radiation decayed-off gases, a circulation water tank for final purification and an exhaustion cylinder by way of connection pipelines in this order. An exhaust gas circulation pipeline is disposed to circulate exhaust gases from an exhaust gas exit pipeline of the recycling water tank to an exhaust gas exit pipeline of the exhaust gas condensator, and a pressure control valve is disposed to the exhaust gas circulation pipeline. This enable to perform a system test for the dehumidification device under a test condition approximate to the load of the dehumidification device under actual operation state, and stabilize both of system flow rate and pressure. (T.M.)

Development of a computational algorithm for the linearization of decay and transmutation chains; Desarrollo de un algoritmo computacional para la linealizacion de cadenas de decaimiento y transmutacion

Energy Technology Data Exchange (ETDEWEB)

Cruz L, C. A.; Francois L, J. L., E-mail: cacl@ier.unam.mx [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac 8532, Col. Progreso, 62550 Jiutepec, Morelos (Mexico)

2017-09-15

One of the most used methodologies to solve Bate man equations, in the problem of burning, is the Tta (Transmutation Trajectory Analysis) method. In this method, a network of decays is broken down into linear elements known as trajectories, through a process known as linearization. In this work an alternative algorithm is shown to find and construct these trajectories, which considers three aspects of linearization: the information -a priori- about the elements that make up decay and transmutation network, the use of a new notation, and in the functions for the treatment of text strings (which are common in most programming languages). One of the main advantages of the algorithm is that can condense the information of a decay and transmutation network into only two vectors. From these is possible to determine how many linear chains can be extracted from the network and even their length (in the case they are not cyclical). Unlike the Deep First Search method, which is widely used for the linearization process, the method proposed in the present work does not have a backward routine and instead occupies a process of compilation, since completes fragments chain instead of going back to the beginning of the trajectories. The developed algorithm can be applied in a general way to the information search and to the linearization of the computational data structures known as trees. It can also be applied to engineering problems where one seeks to calculate the concentration of some substance as a function of time, starting from linear differential equations of balance. (Author)

Table of nuclear reactions and subsequent radioactive dacays induced by 14-MeV neutrons

International Nuclear Information System (INIS)

Tsukada, Kineo

1977-09-01

Compilation of the data on nuclear reactions and subsequent radioactive decays induced by 14-MeV neutrons is presented in tabular form for most of the isotopes available in nature and for some of the artificially-produced isotopes, including the following items: Nuclide (isotopic abundance), type of nuclear reaction, reaction Q-value, reaction product, type of decay, decay Q-value, half-life of reaction product, decay product, maximum reaction cross section, neutron energy for maximum cross section, reaction cross section for 14 MeV neutrons, saturated radioactivity induced by irradiation of a neutron flux of 1 n/cm 2 sec for a mol of atoms, and reference for the cross section. The mass number dependence of (n, γ), (n, 2n), (n, p), (n, d), (n, t), (n, 3 He) and (n, α) reaction cross sections for 14-MeV neutrons is given in figures to show general trends of the cross sections

Radioactivity of dumps in mining areas of the Upper Silesian Coal Basin in Poland

Directory of Open Access Journals (Sweden)

Dorda J.

2012-04-01

Full Text Available Underground coal mining is associated with large quantities of gangue. In the past, the majority of gangue was not utilized but was placed in the vicinity of the coalmines forming cone-shaped dumps. Some of them contained even millions of tons of rock. Nowadays, environmental precautions extort larger utilization of any kind of waste materials, for example in road construction, civil engineering or as stowing in underground abandoned workings. Examination of the composition of waste dumps, including radioactivity, is thus an important issue. The paper presents results of a radiological survey carried out in several dumps located in the Upper Silesian Coal Basin in the south of Poland. Measurements of samples were carried out with the use of a gamma-ray spectrometer. Activity concentration results for the uranium and thorium decay chains are discussed.

Study of the radiation and radioactivity in dairy formulas; Estudio de la radiacion y radiactividad en formulas lacteas

Energy Technology Data Exchange (ETDEWEB)

Mireles G, F.; Pinedo V, J.L.; Quirino T, L.L.; Davila R, J.I.; Rios M, C.; Leal A, B.; Lopez del Rio, H. [Unidad Academica de Estudios Nucleares, UAZ, Cipres 10, Frac. La Penuela, 98068 Zacatecas (Mexico)]. e-mail: fmireles@cantera.reduaz.mx

2006-07-01

The radiation and natural radioactivity is present in the man's food chain, like it is the case of the milk, and it comes from the natural series of radioactive decay of the {sup 238} U, {sup 235} U and {sup 232} Th, and of the {sup 40} K radioisotope. Since the radioisotopes can be found in floor of where its are transferred to the grasses and in the water that serve as food and of drinking to the cows, then to enter the milk and its derived to the human consumption. In this work it is presented the study of the radiation and gamma radioactivity of 40 samples of dairy formulas of the trademarks and presentations more sold in the market of the private and public sectors. The measurements of the gamma ray spectra were carried out with a spectrometry system based on an Hyper pure Germanium detector (HPGe). The detector has a resolution (FWHM) of 1.9 keV for an energy of the gamma ray of 1.332 keV of the {sup 60} Co. This study presents the results of the concentration in activity of dairy formulations of the radioisotopes of interest. Also, the results are related with possible damages to the health. (Author)

Monitoring Programme of Radionuclide Migration Through Food Chains at Low and Intermediate Level Radioactive Waste Repository in Trgoska Gora Mountain

International Nuclear Information System (INIS)

Schaller, A.; Lokner, V.; Kucar Dragicevic, S.; Subasic, D.; Barisic, D.

2001-01-01

Full text: Basic objective of the paper is to prepare a comprehensive programme of monitoring at the preferred site for low and intermediate level radioactive waste repository in the region of Trgovska Gora mountain. The programme is based on available information regarding hydrogeology, lithostratigraphy, tectonics, seismotectonics, geomorphology, meteorology, bioecology, demography and other site relevant disciplines. It is supposed to ensure (1) identification of the zero state at the broader region of the Trgovska gora mountain, and (2) to underline activities needed for monitoring of concentrations of expected radionuclides throughout possible pathways (particularly through food chains) that would migrate to the biosphere in the period after start of radioactive waste repository operation. Inventory of radionuclides contained in the radioactive waste to be disposed of at the site is naturally an important element of the programme structure. There should be identified those radionuclides which concentrations require to be monitored. Concentration measuring methods are proposed in the article. In addition, relevant aquatic and terrestrial organisms, serving as bioindicators, are identified. Types, quantities, frequency and methodology of sampling present an important part of the monitoring programme. Determination of monitoring sites for undertaking particular types of sampling (e.g. stream waters, stream sediment, detritus, ichtiofauna, groundwater, terrestrial organisms, honey, etc.), presenting an important aspect of a well-organised monitoring programme, is also included into this presentation. (author)

The reaction {sup 48}Ca+{sup 248}Cm{yields}{sup 296}116{sup *} studied at the GSI-SHIP

Energy Technology Data Exchange (ETDEWEB)

Hofmann, S. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Goethe-Universitaet Frankfurt, Institut fuer Physik, Frankfurt (Germany); Heinz, S.; Mann, R.; Khuyagbaatar, J.; Ackermann, D.; Barth, W.; Block, M.; Burkhard, H.G.; Comas, V.F.; Dahl, L.; Heredia, J.A.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Muenzenberg, G.; Tinschert, K. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Maurer, J.; Hessberger, F.P. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Johannes Gutenberg-Universitaet, Helmholtz-Institut Mainz, Mainz (Germany); Antalic, S.; Saro, S. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Eberhardt, K.; Kratz, J.V.; Runke, J.; Thoerle-Pospiech, P.; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Gostic, J.; Henderson, R.A.; Kenneally, J.M.; Moody, K.J.; Nelson, S.L.; Shaughnessy, D.A.; Stoyer, M.A.; Wilk, P.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Leino, M.; Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

2012-05-15

The synthesis of element 116 in fusion-evaporation reactions of a {sup 48}Ca beam with radioactive {sup 248}Cm targets was studied at the velocity filter SHIP of GSI in Darmstadt. At excitation energies of the compound nuclei of 40.9MeV, four decay chains were measured, which were assigned to the isotope {sup 292}116, and one chain, which was assigned to {sup 293}116. Measured cross-sections of (3.4{sub -1.6}{sup +2.7})pb and (0.9{sub -0.7}{sup +2.1}), respectively, and decay data of the chains agree with data measured previously at the Flerov Laboratory of Nuclear Reactions in Dubna. As a new result, one {alpha}-decay chain was measured, which terminates after four {alpha} decays by spontaneous fission. The {alpha} energies of the second-to-fourth decay are considerably higher than those measured for the {alpha} decays of {sup 289}114, {sup 285}Cn, and {sup 281}Ds and the spontaneous fission half-life is significantly longer than that of {sup 277}Hs measured in previous experiments. A possible assignment is discussed in the frame of excited quasiparticle states of nuclei populated in the decay chain from {sup 293}116. Also other possible assignments were considered and are discussed. At an excitation energy of 45.0MeV no events were observed resulting in a one-event cross-section limit of 1.6 pb. The technical aspects related with the use of radioactive target material at SHIP are described in detail. The experience gained in this experiment will serve as a basis for future experiments aiming to study still heavier elements at the velocity filter SHIP. (orig.)

Unexpected high-energy γ emission from decaying exotic nuclei

Directory of Open Access Journals (Sweden)

A. Gottardo

2017-09-01

Full Text Available The N=52 Ga83 β decay was studied at ALTO. The radioactive 83Ga beam was produced through the ISOL photofission technique and collected on a movable tape for the measurement of γ-ray emission following β decay. While β-delayed neutron emission has been measured to be 56–85% of the decay path, in this experiment an unexpected high-energy 5–9 MeV γ-ray yield of 16(4% was observed, coming from states several MeVs above the neutron separation threshold. This result is compared with cutting-edge QRPA calculations, which show that when neutrons deeply bound in the core of the nucleus decay into protons via a Gamow–Teller transition, they give rise to a dipolar oscillation of nuclear matter in the nucleus. This leads to large electromagnetic transition probabilities which can compete with neutron emission, thus affecting the β-decay path. This process is enhanced by an excess of neutrons on the nuclear surface and may thus be a common feature for very neutron-rich isotopes, challenging the present understanding of decay properties of exotic nuclei.

Decay Studies of Very Neutron Rich Nuclei near 78Ni

International Nuclear Information System (INIS)

Winger, J. A.; Ilyushkin, S.; Korgul, A.; Gross, Carl J; Rykaczewski, Krzysztof Piotr; Batchelder, J. C.; Goodin, C.; Grzywacz, R.; Hamilton, J. H.; Krolas, W.; Liddick, Sean; Mazzocchi, C.; Nelson, C.; Padgett, Stephen; Piechaczek, A.; Rajabali, M. M.; Shapira, Dan; Zganjar, E. F.

2008-01-01

The properties of beta-gamma and beta-delayed neutron emission from 76-79 Cu and 83-85 Ga were measured at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. Selected results on the decay properties of copper isotopes are briefly presented and discussed

High-level radioactive waste isolation by incorporation in silicate rock

International Nuclear Information System (INIS)

Schwartz, L.L.; Cohen, J.J.; Lewis, A.E.; Braun, R.L.

1978-01-01

A number of technical possibilities for isolating high-level radioactive materials have been theoretically investigated at various times and places. Isolating such wastes deep underground to ensure long term removal from the biosphere is one such possibility. The present concept involves as a first step creating the necessary void space at considerable depth, say 2 to 5 km, in a very-low-permeability silicate medium such as shale. Waste in dry, calcined or vitrified form is then lowered into the void space, and the access hole or shaft sealed. Energy released by the radioactive decay raises the temperature to a point where the surrounding rock begins to melt. The waste is then dissolved in it. The extent of this melt region grows until the heat generated is balanced by conduction away from the molten zone. Resolidification then begins, and ends when the radioactive decay has progressed to the point that the temperature falls below the melting point of the rock-waste solution. Calculations are presented showing the growth and resolidification process. A nuclear explosion is one way of creating the void space. (author)

Alpha decay properties of heavy and superheavy elements

International Nuclear Information System (INIS)

Vigila Bai, G.M. Carmel; Umai Parvathiy, J.

2015-01-01

Analysing accurately the lifetimes of α-decay chains is an important tool to detect and study the properties of superheavy nuclei. 48 Ca is used in the synthesis of superheavy nuclei Z = 106-118 at Dubna. The experimental work of 48 Ca projectiles at Dubna has given an opportunity to study the superheavy element (SHE). Here, the α-decay properties for Z = 106-118 are evaluated using our CYE model and are compared with the available experimental and theoretical values. (author)

Microscopic beta and gamma data for decay-heat needs

International Nuclear Information System (INIS)

Dickens, J.K.

1983-01-01

Microscopic beta and gamma data for decay-heat needs are defined as absolute-intensity spectral distributions of beta and gamma rays following radioactive decay of radionuclides created by, or following, the fission process. Four well-known evaluated data files, namely the US ENDF/B-V, the UK UKFPDD-2, the French BDN (for fission products), and the Japanese JNDC Nuclear Data Library, are reviewed. Comments regarding the analyses of experimental data (particularly gamma-ray data) are given; the need for complete beta-ray spectral measurements is emphasized. Suggestions on goals for near-term future experimental measurements are presented. 34 references

Effective liquid drop description for alpha decay of atomic nuclei

International Nuclear Information System (INIS)

Tavares, O.A.P.; Duarte, S.B.; Rodriguez, O.; Guzman, F.; Goncalves, M.; Garcia, F.

1998-06-01

Alpha decay half-lives are presented in the framework of an effective liquid drop model for different combination of mass transfer descriptions and inertia coefficients. Calculated half-life-values for ground-state to ground-state favoured alpha transitions are compared with available, updated experimental data. Results have shown that the present model is very suitable to treat the alpha decay process on equal foot as cluster radioactivity and cold fission processes. Better agreement with the data is found when the sub-set of even-even alpha emitters are considered in the calculation. (author)

Dose estimation from residual and fallout radioactivity, 1

International Nuclear Information System (INIS)

Takeshita, Kenji

1975-01-01

External dose rates and cumulative doses for early entrants from areal surveys and simulated experiments are reviewed. The average cumulative doses to infinity at the hypocenters were 101 rad in Hiroshima and 32 rad in Nagasaki, with a variation of about 60 percent. Radioactive fallout areas nearly matched the ''black rain'' areas in Nagasaki and in Hiroshima. Radioactivity in the fallout areas was affected by radioactive decay and by the leaching and dissipation by rains. Considering these factors, the cumulative dose to infinity in the fallout area of Hiroshima was estimated to be 13 rad, excluding internal radiation doses from inhaled and ingested radionuclides. Attempts to estimate radiation dose from internally deposited radionuclides are also described. (auth.)

Complex degradation processes lead to non-exponential decay patterns and age-dependent decay rates of messenger RNA.

Directory of Open Access Journals (Sweden)

Carlus Deneke

Full Text Available Experimental studies on mRNA stability have established several, qualitatively distinct decay patterns for the amount of mRNA within the living cell. Furthermore, a variety of different and complex biochemical pathways for mRNA degradation have been identified. The central aim of this paper is to bring together both the experimental evidence about the decay patterns and the biochemical knowledge about the multi-step nature of mRNA degradation in a coherent mathematical theory. We first introduce a mathematical relationship between the mRNA decay pattern and the lifetime distribution of individual mRNA molecules. This relationship reveals that the mRNA decay patterns at steady state expression level must obey a general convexity condition, which applies to any degradation mechanism. Next, we develop a theory, formulated as a Markov chain model, that recapitulates some aspects of the multi-step nature of mRNA degradation. We apply our theory to experimental data for yeast and explicitly derive the lifetime distribution of the corresponding mRNAs. Thereby, we show how to extract single-molecule properties of an mRNA, such as the age-dependent decay rate and the residual lifetime. Finally, we analyze the decay patterns of the whole translatome of yeast cells and show that yeast mRNAs can be grouped into three broad classes that exhibit three distinct decay patterns. This paper provides both a method to accurately analyze non-exponential mRNA decay patterns and a tool to validate different models of degradation using decay data.

Handbook of radioactivity analysis. Second edition

International Nuclear Information System (INIS)

L'Annunziata, M.

2003-07-01

This updated and much expanded Second Edition is an authoritative handbook providing the principles, practical techniques, and procedures for the accurate measurement of radioactivity from the very low levels encountered in the environment to higher levels measured in radioisotope research, clinical laboratories, biological sciences, radionuclide standardization, nuclear medicine, nuclear power, fuel cycle facilities, and in the implementation of nuclear safeguards. The book describes the preparation of samples from a wide variety of matrices, assists the investigator or technician in the selection and use of appropriate radiation detectors, and presents state-of-the-art methods of analysis. Fundamentals of radioactivity properties, radionuclide decay, the calculations involved, and methods of detection provide the basis for a thorough understanding of the analytical procedures. The Handbook of Radioactivity Analysis, Second Edition is suitable as a teaching text for university and professional training courses

Modification of the rate of β-decay by chiral molecular environment

International Nuclear Information System (INIS)

Garay, A.S.; Biological Research Center, Szeged

2000-01-01

The radioactive isotope 32 P in the form of phosphoric acid (H 3 32 PO 4 ) and 22 Na in the form of sodium chloride ( 22 NaCl), were dissolved in R and S mirror image chiral solvents of 2-phenylbutyric acid (PBA) and diethyltartrate (DET). Then their decay rates were determined and compared to each other, to their decay rates in water and to their decay rates in racemic mixtures. It was found that 32 P decayed significantly faster if dissolved in R-PBA than in S-PBA. Similarly, 22 Na decayed significantly faster if dissolved in R-DET than in S-DET. Evidently the decay rates are sensitive to the right- and left-handed potential fields of the solvent molecules. However, the decay rate of 32 P was insensitive to the chiral senses of the DET solvents. Similarly, the decay rate of 22 Na was insensitive to the chiral senses of the PBA solvents. This can be tentatively explained by the interactions between the solvents and the solutes. It was also observed that in the first ten percent of the half-life time the decay of 32 P and particularly the decay of 22 Na often showed some deviation from the exponential behavior. This effect is chirality-dependent. (author)

Regulations and decisions in environmental impact assessment of residues radioactivity content

International Nuclear Information System (INIS)

Santos, Adir Janete Godoy dos

2005-01-01

Surveillance of natural radionuclides in the environment did not have high priority over many years compared to that of man-made radioactivity. There is, however, an increasing interest in such measurements since enhanced exposure to natural radioactivity is receiving the same legal weight as any other radiation exposure. In this context the surveillance of technologically enhanced naturally occurring materials, called TENORM becomes important. In Brazil, the industries of processing and chemical compounds production were developed based on mining, milling, transformation and manufacture of ores from sedimentary origin, ignea or metamorphic, which must determine the radioactive composition of the generated solid wastes and residues. Many solids residues stored in the environment has been of environmental concern facing the industries and environmentalists in Brazil as it presents a potential threat to the surrounding environment and to individuals occupationally exposed. Radiation protection regulations have not been applied yet to these industries, as the Brazilian regulatory agency (Comissao Nacional de Energia Nuclear - CNEN) has only recently published a regulatory guide concerning mining and milling of naturally occurring radioactive materials, which may generate enhanced concentrations of radionuclides. With respect to external and internal exposure to natural radionuclides from the solid residues storage, the nuclides of 232 Th, 235 U and 238 U decay chains are relevant, due to the exposure of workers as well as of members of the public. Radionuclides released from a source can be present as ions, molecules, complexes, mononuclear or polynuclear species, colloids, pseudocolloids, particles or fragments varying in size (nominal molecular mass), structure, morphology, density, valence and charge properties. One of the main points in environmental impact assessment is to identify whether the chemical availability is under influence of these speciation

Production and decay of the heaviest odd-Z nuclei in the 249Bk + 48Ca reaction

International Nuclear Information System (INIS)

Oganessian, Yu Ts; Abdullin, F Sh; Dmitriev, S N; Itkis, M G; Polyakov, A N; Alexander, C; Binder, J; Boll, R A; Ezold, J; Felker, K; Grzywacz, R K; Miernik, K; Roberto, J B; Gostic, J M; Henderson, R A; Moody, K J; Hamilton, J H; Ramayya, A V; Miller, D; Ryabinin, M A

2015-01-01

The reaction of 249 Bk with 48 Ca has been investigated with an aim of synthesizing and studying the decay properties of isotopes of the new element 117. The experiments were performed at five projectile energies (in two runs, in 2009-2010 and 2012) and with a total beam dose of 48 Ca ions of about 9x10 19 The experiments yielded data on a-decay characteristics and excitation functions of the produced nuclei that establish these to be 293 117 and 294 117 – the products of the 4n- and 3n-evaporation channels, respectively. In total, we have observed 20 decay chains of Z=117 nuclides. The cross sections were measured to be 1.1 pb for the 3n and 2.4 pb for the 4n-reaction channel. The new 289 115 events, populated by α decay of 117, demonstrate the same decay properties as those observed for 115 produced in the 243 Am( 48 Ca,2n) reaction thus providing cross-bombardment evidence. In addition, a single decay of 294 118 was observed from the reaction with 249 Cf – a result of the in-growth of 249 Cf in the 249 Bk target. The observed decay chain of 294 118 is in good agreement with decay properties obtained in 2002-2005 in the experiments with the reaction 249 Cf( 48 Ca,3n) 294 118. The energies and half-lives of the odd-Z isotopes observed in the 117 decay chains together with the results obtained for lower-Z superheavy nuclei demonstrate enhancement of nuclear stability with increasing neutron number towards the predicted new magic number N=184

Study of two-proton radioactivity within the relativistic mean-field plus BCS approach

International Nuclear Information System (INIS)

Singh, D.; Saxena, G.

2012-01-01

Inspired by recent experimental studies of two-proton radioactivity in the light-medium mass region, we have employed relativistic mean-field plus state-dependent BCS approach (RMF+BCS) to study the ground state properties of selected even-Z nuclei in the region 20 ≤ Z ≤ 40. It is found that the effective potential barrier provided by the Coulomb interaction and that due to centrifugal force may cause a long delay in the decay of some of the nuclei even with small negative proton separation energy. This may cause the existence of proton-rich nuclei beyond the proton drip-line. Nuclei 38 Ti, 42 Cr, 45 Fe, 48 Ni, 55 Zn, 60 Ge, 63, 64 Se, 68 Kr, 72 Sr and 76 Zr are found to be the potential candidates for exhibiting two-proton radioactivity in the region 20 ≤ Z ≤ 40. The reliability of these predictions is further strengthened by the agreement of the calculated results for the ground state properties such as binding energy, one- and two-proton separation energy, proton and neutron radii, and deformation with the available experimental data for the entire chain of the isotopes of the nuclei in the region 20 ≤ Z ≤ 40. (author)

New Decay Studies of 66Ga

Science.gov (United States)

Kumar, Suresh; Ahmad, I.; Carpenter, M. P.; Chen, J.; Greene, J. P.; Kondev, F. G.; Zhu, S.

2014-03-01

High-energy γ rays with energies up to 5.0 MeV are emitted in the radioactive decay of 66Ga (T1/2 = 9.49 h). Thus, this radionuclide appears to be a suitable candidate for energy and efficiency calibrations of high-resolution, γ-ray spectrometers that are employed in studies of very neutron-rich nuclei which have large Qβ values. In addition, accurate emission probabilities of this isotope are of interest to medical imaging applications, owing to the existence of large β+ decay branches, which need to be characterized with better accuracy. Decay studies of 66Ga were initiated using the γ-ray spectroscopy technique. The source was produced by means of the 66Zn(p,n) reaction at a beam energy of 12 MeV. Singles and γ - γ coincidences measurements were carried out using a single Ge detector and Gammasphere, respectively. The previously known 66Ga decay scheme was extended and many new γ rays were placed in the daughter nuclide 66Zn. The work at ANL was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. S. Kumar acknowledges support from the Indo-US Science and Technology Forum for the award of a Research Fellowship.

Evaluation of thermal hydraulics characteristics of natural cooling low level radioactive waste storage system

International Nuclear Information System (INIS)

Yoshii, Toshihiro; Iwaki, Chikako; Ikeda, Tatsumi; Ikeda, Hiroshi; Koyama, Tomonori; Usui, Nobuhiko; Watanabe, Hisao; Masaki, Yoshikazu

2012-01-01

It is necessary to design a low level radioactive waste storage system so that the decay heat of radioactive waste does not breach the structural safety limit. Currently, this waste storage system is designed as a natural cooling system, which continuously cools the radioactive waste without an active device. It consists simply of a storage pit for radioactive waste and air inlet and outlet ducts. The radioactive waste is cooled by natural convective air flow, which is generated by the buoyancy of heated air due to the decay heat of radioactive waste. It is important to clarify the flow characteristics in the systems in order to evaluate the cooling performance. The air mass flow rate through the system is determined by the balance between the natural convective flow force and pressure loss within the system. Therefore, the pressure drop and flow pattern in the waste storage pit are important flow characteristics. In this study, the pressure drop and air temperature distribution, greatly influenced by the flow pattern in the pit, were measured using a 1/5 scale model and compared with the results obtained from CFD. Flow network analysis, which is a simple model that simulates the flow by nodes and junctions, was conducted and its validity was confirmed by experimental results and CFD. (author)

Radioactive waste management and disposal in Australia

International Nuclear Information System (INIS)

Harries, J.R.

1997-01-01

A national near-surface repository at a remote and arid location is proposed for the disposal of solid low-level and short-lived intermediate-level radioactive wastes in Australia. The repository will be designed to isolate the radioactive waste from the human environment under controlled conditions and for a period long enough for the radioactivity to decay to low levels. Compared to countries that have nuclear power programs, the amount of waste in Australia is relatively small. Nevertheless, the need for a national disposal facility for solid low-level radioactive and short-lived intermediate-level radioactive wastes is widely recognised and the Federal Government is in the process of selecting a site for a national near-surface disposal facility for low and short-lived intermediate level wastes. Some near surface disposal facilities already exist in Australia, including tailings dams at uranium mines and the Mt Walton East Intractable Waste Disposal Facility in Western Australia which includes a near surface repository for low level wastes originating in Western Australia. 7 refs, 1 fig., 2 tabs

Analytical approach to the evaluation of nuclide transmutations

International Nuclear Information System (INIS)

Vukadin, Z.; Osmokrovic, P.

1995-01-01

Analytical approach to the evaluation of nuclide concentrations in a transmutation chain is presented. Non singular Bateman coefficients and depletion functions are used to overcome numerical difficulties when applying well-known Bateman solution of a simple radioactive decay. Method enables evaluation of complete decay chains without elimination of short lived radionuclides. It is efficient and accurate. Practical application of the method is demonstrated by computing the neptunium series inventory in used Candu TM fuel. (author)

PRAMANA Cluster radioactivity in xenon isotopes

Indian Academy of Sciences (India)

exotic decay or cluster radioactivity was first predicted by sandulescu et al [1] in. 1980 on the basis of ... separator by 58Ni(58Ni, 2n) reaction and carbon clusters were searched for by means of solid state nuclear ..... Lett. 55, 582 (1985). [22] D N Poenaru, W Greiner, K Depta, M Ivascu, D Mazilu and A Sandulescu, At. Data.

Simulation of radon short lived decay daughters' inhalation using the lung compartmental model

International Nuclear Information System (INIS)

Tomulescu, Vlad C.

2002-01-01

Radon and its short-lived decay daughters are the main source of radiation on natural ways for population. The radon gas, released from soil, water or construction materials is producing by radioactive decay the following solid daughters: Po-218, Bi-214, Pb-214, and Po-214, which can attach to aerosols, and consequently penetrate the organism by inhalation. The human respiratory tract can be approximated by aid of a compartment model that takes into account the different anatomical structures exposed to contamination and irradiation, as well as the respective physiological processes. This model is associated to a mathematical equation system that describes the behavior of the radioactive material inside the body. The results represent the dose equivalent on different organs and tissues, as a function of subject and the activity performed in contaminating environment. (author)

Nuclear structure from radioactive decay. Annual progress report

International Nuclear Information System (INIS)

Wood, J.L.

1986-01-01

The primary focus has been studies of intruder states and shape coexistence in the neutron-deficient Z equal to 82 region. Most notably, the structure of the neutron-deficient Au isotopes has been studied by on-line decay scheme spectroscopy of mass-separated isotopes at UNISOR, by on-line low-temperature nuclear orientation of mass-separated isotopes at LISOL, and by on-line laser atomic hyperfine spectroscopy of mass-separated isotopes at ISOLDE. Theoretical studies of neutron-deficient Au isotopes have been made. The most dramatic result is the observation of a sudden large increase in the mean-square charge radius between 187 Au and 186 Au, seen in the laser spectroscopy measurements as ISOLDE

Nuclear structure from radioactive decay: Annual progress report

International Nuclear Information System (INIS)

Wood, J.L.

1987-01-01

The primary focus this year has been studies of intruder states and shape coexistence in the neutron-deficient Z ∼ 82 region. Most notably, the existence and conditions for the occurrence of electric monopole (E0) transitions have been considerably clarified. This has been a topic of considerable confusion. On-line decay scheme spectroscopy of mass-separated isotopes at UNISOR (in a collaboration with LSU) has now completely resolved all points of disagreement. These studies are part of a larger program directed towards building a complete picture of shape coexistence. It is becoming evident that E0 transitions are a key signature to shape coexistence. Thus, their correct identification and location are crucial

Management of radioactive medical waste

International Nuclear Information System (INIS)

Deschamps, S.; Mathey, J.C.

1996-01-01

Hospitals are producers of small amounts of radioactive waste. Current legislation details exactly how hospitals should manage it. Sealed sources are returned to suppliers. Disposal of unsealed sources, liquid or solid, depends upon their half-life: short-lived radioisotopes (half-life less than two months) are stocked on site while they decay; isotopes with longer half-lives (greater than two months) are handled by a specialist organization (ANDRA). (authors). 8 refs

Tunnel current across linear homocatenated germanium chains

International Nuclear Information System (INIS)

Matsuura, Yukihito

2014-01-01

The electronic transport properties of germanium oligomers catenating into linear chains (linear Ge chains) have been theoretically studied using first principle methods. The conduction mechanism of a Ge chain sandwiched between gold electrodes was analyzed based on the density of states and the eigenstates of the molecule in a two-probe environment. Like that of silicon chains (Si chains), the highest occupied molecular orbital of Ge chains contains the extended σ-conjugation of Ge 4p orbitals at energy levels close to the Fermi level; this is in contrast to the electronic properties of linear carbon chains. Furthermore, the conductance of a Ge chain is expected to decrease exponentially with molecular length L. The decay constant β, which is defined as e −βL , of a Ge chain is similar to that of a Si chain, whereas the conductance of the Ge chains is higher than that of Si chains even though the Ge–Ge bond length is longer than the Si–Si bond length

A simulation for radioactive decay and the absorption of radiation

International Nuclear Information System (INIS)

Anon.

1987-01-01

The purpose of this article is to derive and discuss these exponential laws for the benefit of teachers and interested pupils, and to discuss a simulation of the above phenoma should radioactive sources and Geiger-Mueller counters not be available in any particular school laboratory. The simulation can also be done by computer

A software for a quick assessment of the consequences of a radioactive fallout on the food chain: application to a tropical environment

International Nuclear Information System (INIS)

Laylavoix, F.; Grouzelle, C.; Baudot, M.F.

1995-01-01

A software has been developed for a fast assessment of the consequences of a radioactive fallout on the food chain. From the surface activity measured 24 h after deposition, it computes the dose ingested by the population on the 60th day of exposure; this duration corresponds to 2 or 4 mechanical clearance half-lives of the radionuclides at the vegetal surface. Particular attention was paid to easy access to specific local parameters, conviviality and possibility to be used on any MS.DOS operated PC. (authors). 17 refs., 1 fig

Control of radioactive material transport in sodium-cooled reactors

International Nuclear Information System (INIS)

Brehm, W.F.

1980-03-01

The Radioactivity Control Technology (RCT) program was established by the Department of Energy to develop and demonstrate methods to control radionuclide transport to ex-core regions of sodium-cooled reactors. This radioactive material is contained within the reactor heat transport system with any release to the environment well below limits established by regulations. However, maintenance, repair, decontamination, and disposal operations potentially expose plant workers to radiation fields arising from radionuclides transported to primary system components. This paper deals with radioactive material generated and transported during steady-state operation, which remains after 24 Na decay. Potential release of radioactivity during postulated accident conditions is not discussed. The control methods for radionuclide transport, with emphasis on new information obtained since the last Environmental Control Symposium, are described. Development of control methods is an achievable goal

Absolute radioactivity measurements

International Nuclear Information System (INIS)

Weiss, H.M.

1983-01-01

The radioactivity of a thin specimen can be determined directly, i.e. without reference to a standard and without knowing decay data, except for half-life, by means of counting at a given solid angle and by 4 πβ-γ coincidence measurement. In accordance with section 7 of the law on units, it is the task of PTB not only to represent the units and its derivation, but also to work out methods of adjusting national prototypes and normals to international prototypes and etalons in accordance with the international metre convention. (DG) [de

Marine sediments as a radioactive pollution repository in the world

International Nuclear Information System (INIS)

Navarrete, J.M.; Mueller, G.; Zuniga, M.A.; Camacho, M.; Espinosa, G.; Golzarri, J.I.

2014-01-01

During a time period little longer than 60 years, it has been created a radioactive pollution background over the natural one, which started in 1945 and it has been growing up since then, due to several nuclear tests, minor nuclear reactors failure and four major accidents: Wind Scale, Three Mile Island, Chernobyl and Fukushima. This radioactive polluting background can be easily detected through 137 Cs fission product, which by the effect of wind, river currents and rain has been accumulated in marine sediments, mainly because sea represents about 80 % of earth's surface. Since energy demand has been growing up with no interruption during last two centuries, and nuclear energy seems to be the largest available source, it is very likely a great expansion of nuclear energy during twenty-first century. So, this paper presents results obtained in strategic points of the two large littorals in Mexico: Gulf and Pacific Ocean, as an attempt to establish there some figure to evaluate the present radioactive pollution. An adequate figure to do it, seems to be the quotient of activity per gram of 137 Cs in marine sediments (Bq 137 Cs/g), divided by activity per gram of 40 K natural radioactivity (Bq 40 K/g). When this result is multiplied by 100 the percentage of polluting radioactivity ( 137 Cs) related to natural radioactivity ( 40 K) is obtained. This percentage seems to be useful to evaluate the importance of radioactive pollution from 4 points of view: a) calculate the extent of already radioactive pollution present in the seas of world; b) avoid the panic in case of nuclear accidents, c) what will be the growing up rate in the future; d) if it is possible to keep one decreasing rate at same decaying rate of 137 Cs (t 1/2 = 30.07 years), since from 1945, starting time of radioactive pollution, it has decayed only about 2.2 half lives. (author)

Development of a computer code for low-and intermediate-level radioactive waste disposal safety assessment

International Nuclear Information System (INIS)

Park, J. W.; Kim, C. L.; Lee, E. Y.; Lee, Y. M.; Kang, C. H.; Zhou, W.; Kozak, M. W.

2002-01-01

A safety assessment code, called SAGE (Safety Assessment Groundwater Evaluation), has been developed to describe post-closure radionuclide releases and potential radiological doses for low- and intermediate-level radioactive waste (LILW) disposal in an engineered vault facility in Korea. The conceptual model implemented in the code is focused on the release of radionuclide from a gradually degrading engineered barrier system to an underlying unsaturated zone, thence to a saturated groundwater zone. The radionuclide transport equations are solved by spatially discretizing the disposal system into a series of compartments. Mass transfer between compartments is by diffusion/dispersion and advection. In all compartments, radionuclides are decayed either as a single-member chain or as multi-member chains. The biosphere is represented as a set of steady-state, radionuclide-specific pathway dose conversion factors that are multiplied by the appropriate release rate from the far field for each pathway. The code has the capability to treat input parameters either deterministically or probabilistically. Parameter input is achieved through a user-friendly Graphical User Interface. An application is presented, which is compared against safety assessment results from the other computer codes, to benchmark the reliability of system-level conceptual modeling of the code

Simple description of cluster radioactivity

International Nuclear Information System (INIS)

Tavares, O.A.P.; Medeiros, E.L.

2012-05-01

The partial half-life of radioactive decay of nuclei by the emission of fragments heavier than the alpha particle, such as the emission of carbon, oxygen, neon, magnesium, and silicon isotopes from translead nuclei (known as cluster radioactivity), is re-evaluated in the framework of a semiempirical, one-parameter model based on the quantum mechanical tunneling mechanism through a potential barrier where the Coulomb, centrifugal, and overlapping contributions to the barrier are considered within the spherical nucleus approximation. This treatment has shown not only very adequate to t all the existing half-life data, but also to give more reliable half-life predictions for new, yet unmeasured cases of spontaneous emission of massive nuclear fragments both from heavy and intermediate-mass parent nuclei as well. (author)

Beta decay of highly charged ions

International Nuclear Information System (INIS)

Litvinov, Yuri A; Bosch, Fritz

2011-01-01

Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

First design for the optics of the decay ring for the beta-beams

International Nuclear Information System (INIS)

Chance, A.; Payet, J.

2006-03-01

The aim of the beta-beams is to produce pure electronic neutrino and anti-neutrino highly energetic beams, coming from beta radioactive disintegration decay of the 18 Ne 10+ and 6 He 2+ , directed to experiment situated in the Frejus tunnel. The high ion intensities are stored in a ring, until the ions decay. The losses due to the decay of the radioactive ions are compensated with regular injections. These should be done in presence of the circulating beam. The new ions are injected at a different energy from the stored beam energy, the design of the ring must enable this type of injection and accept the injected and stored beams. In this note, we will focus on the study of the design of such a ring at the first and second orders. We have reached the constraint on the dispersion in the injection section: a horizontal dispersion superior to 10 m with β x = 20 m. We have put sextupoles in the arcs to correct the chromaticity. In the same time, we have compensated the third order resonances to have a large enough dynamic aperture. So the decay ring accepts injected and stored beams. In a top-down approach, the high stored intensities impose to take into account the space charge effects. However, due to the merging, the beam blows up after each injection in the longitudinal space charge, which imposes to include a momentum collimation section in the decay ring

[Nationwide survey on radioactive waste management related to positron emission tomography in Japan].

Science.gov (United States)

Nagaoka, Hiroaki; Watanabe, Hiroshi; Yamaguchi, Ichiro; Fujibuchi, Toshioh; Kida, Tetsuo; Tanaka, Shinji

2009-12-20

A clearance system for medical radioactive solid waste has not yet been implemented in Japan. Since 2004 new regulations have allowed institutions using positron emission tomography(PET)to handle totally decayed radioactive waste as non-radioactive waste after decay-in-storage. It was expected that this new regulation would mediate the installation of clearance systems in Japan. In order to assess the current situation of radiation safety management in PET institutions, we conducted a nationwide survey. The study design was a cross-sectional descriptive study conducted by questionnaire. The subjects of this survey were all the PET institutions in Japan. Among 224 institutes, 128 institutes are equipped with cyclotrons and 96 institutes are not. The number of returned questionnaires was 138. Among institutes that are using delivered radiopharmaceuticals, 80% treat their waste as non-radioactive according to the new regulation. The impact of new regulations for reducing radioactive waste in PET institutes without a cyclotron was estimated at about $400 thousand per year. The main concern of medical institutes was assessment of the contamination caused by by-products of radioactive nuclides generated in target water during the operation of a cyclotron. It was thought that a rational rule based on scientific risk management should be established because these by-products of radioactive nuclides are negligible for radiation safety. New regulation has had a good influence on medical PET institutes, and it is expected that a clearance system for medical radioactive waste will be introduced in the near future, following these recent experiences in PET institutes.

Cluster radioactivity and very asymmetric fission through quasi-molecular shapes

International Nuclear Information System (INIS)

Royer, G.

1997-01-01

The decay of radioactive nuclei which emit heavy clusters like C, O, Ne, Mg and Si has been studied in the fission valley which leads one spherical nucleus towards two spherical touching nuclei before crossing the barrier. Assuming volume conservation, the deformation energy has been calculated within a generalized liquid drop model taking into account the proximity effects between the cluster and the daughter nucleus. The theoretical partial half-lives obtained within the WKB barrier penetration probability are in good agreement with the experimental data for the heaviest clusters. The Ne, Mg and Si emission looks like a very-asymmetric spontaneous fission. The 14 C radioactivity is not correctly described within the fission hypothesis. The 14 C and apparently also the 20 O are probably pre-born in the parent nucleus, the emission being similar to the α decay process. (author)

Method of monitoring volume activity of natural radioactive aerosol

International Nuclear Information System (INIS)

Dvorak, V.

1980-01-01

The method of monitoring radioactivity of a aerosol trapped, eg., with a filter is based on counting quasi-coincidences of the RaC-RaC' and ThC-ThC' decay. The first electronic unit counts quasi-coincidences at a time interval proportional to the ThC' half-life while the second electronic unit counts quasi-coincidences at a time interval proportional to the RaC' half-life, reduced by the time interval of the first electronic unit. The quasi-coincidences are evaluated of the RaC-RaC' decay independently of the ThC-ThC' quasi-coincidences and the decay products of the trapped radon and thoron gases are thus offset separately. (J.P.)

Radiological Risk Assessment and Survey of Radioactive Contamination for Foodstuffs

International Nuclear Information System (INIS)

Lee, W.R.; Lee, C.W.; Choi, K.S.

2007-11-01

After the Chernobyl nuclear accident in 1986, a radiological dose assessment and a survey of a radioactive contamination for foodstuffs have been investigated by many countries such as EU, Japan, USA. In the case of Japan which is similar to our country for the imported regions of foodstuffs, there were some instances of the excess for regulation on the maximum permitted levels of radioactive contamination among some imported foodstuffs. Concerns about the radioactive contamination of foodstuffs are increased because of the recently special situation (Nuclear test of North Korea). The purpose of this study is a radiological dose assessment and a survey of a radioactive contamination for foodstuffs in order to reduce the probability of intake of contaminated foodstuffs. Analytical results of the collected samples are below MDA. In this project, the model of radiological dose assessment via the food chain was also developed and radiological dose assessment was conducted based on surveys results of a radioactive contamination for foodstuffs in the Korean open markets since 2002. The results of radiological dose assessment are far below international reference level. It shows that public radiation exposure via food chain is well controlled within the international guide level. However, the radioactive contamination research of imported foodstuffs should be continuous considering the special situation(nuclear test of North Korea). These results are used to manage the radioactive contamination of the imported foodstuffs and also amend the regulation on the maximum permitted levels of radioactive contamination of foodstuffs

Dose and dose commitment calculations from groundwaterborne radio-active elements released from a repository for spent nuclear fuel

International Nuclear Information System (INIS)

Bergstroem, U.

1983-05-01

The turnover of radioactive matter entering the biosphere with groundwater has been studied with regard to exposure and doses to critical groups and populations. Two main recipients, a well and a lake, have been considered for the inflow of groundwaterborne nuclides. Mathematical models of a set of coupled ecosystems on regional, intermediate and global levels have been used for calculations of doses. The intermediate system refers to the Baltic Sea. The mathematical treatment of the model is based upon compartment theory with first order kinetics and also includes products in decay chains. The time-dependent exposures have been studied for certain long-lived nuclides of radiological interest in waste from disposed fuel. Dose and dose commitment have been calculated for different episodes for inflow to the biosphere. (author)

Radioactive isotopes in solid-state physics

CERN Document Server

Deicher, M

2002-01-01

Radioactive atoms have been used in solid-state physics and in material science for many decades. Besides their classical application as tracer for diffusion studies, nuclear techniques such as M\\"ossbauer spectroscopy, perturbed angular correlation, $\\beta$-NMR, and emission channelling have used nuclear properties (via hyperfine interactions or emitted particles) to gain microscopical information on the structural and dynamical properties of solids. During the last decade, the availability of many different radioactive isotopes as a clean ion beam at ISOL facilities such as ISOLDE at CERN has triggered a new era involving methods sensitive for the optical and electronic properties of solids, especially in the field of semiconductor physics. Extremely sensitive spectroscopic techniques like deep-level transient spectroscopy (DLTS), photoluminescence (PL), and Hall effect have gained a new quality by using radioactive isotopes. Because of their decay the chemical origin of an observed electronic and optical b...

Paul Trapping of Radioactive 6He+ Ions and Direct Observation of Their β Decay

International Nuclear Information System (INIS)

Flechard, X.; Lienard, E.; Mery, A.; Rodriguez, D.; Ban, G.; Durand, D.; Duval, F.; Herbane, M.; Labalme, M.; Mauger, F.; Naviliat-Cuncic, O.; Velten, Ph.; Thomas, J. C.

2008-01-01

We demonstrate that abundant quantities of short-lived β unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy 6 He + (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then decelerated, cooled, and bunched by means of the buffer gas cooling technique. More than 10 8 ions have been stored over a measuring period of six days, and about 10 5 decay coincidences between the beta particles and the 6 Li ++ recoiling ions have been recorded. The technique can be extended to other short-lived species, opening new possibilities for trap assisted decay experiments

Some problems in critical use of nuclear decay data

International Nuclear Information System (INIS)

Kawada, Yasushi

1975-01-01

A great variety of radionuclides are utilized at present and they have been increasing steadly in number with the development of science and technology. Therefore, the parameters such as their decay patterns, half lives, kinds of radioactive ray, ratio of energy emission, coefficients of internal conversion, fluorescence yields, etc. should be grasped for RI utilization. This report gives the outline of the present status and some problems for arranging nuclear decay data from the viewpoint of utilizing radioisotopes. The compilation and evaluation of nuclear decay data prevailing at present are summarized in ''Table of Isotopes'' and ''Nuclear Data Sheets'', but some gaps are found between them. Conspicuous gaps are recognized in such data as half life, γ-ray intensity, radiation energy, coefficient of internal conversion, etc. Some problems are also found in the data of fluorescence yield,

The ''invisible'' radioactive scale

International Nuclear Information System (INIS)

Bjoernstad, T.; Ramsoey, T.

1999-04-01

Production and up-concentration of naturally occurring radioactive material (NORM) in the petroleum industry has attracted steadily increasing attention during the last 15 years. Most production engineers today associate this radioactivity with precipitates (scales) and sludges in production tubing, pumps, valves, separators, settling tanks etc., wherever water is being transported or treated. 226 Ra and 228 Ra are the most well known radioactive constituents in scale. Surprisingly little known is the radioactive contamination by 210 Pb and progeny 210 Bi and 210 Po. These are found in combination with 226 Ra in ordinary scale, often in layer of non-radioactive metallic lead in water transportation systems, but also in pure gas and condensate handling systems ''unsupported'' by 226 Ra, but due to transportation and decay of the noble gas 222 Rn in NG/LNG. This latter contamination may be rather thin, in some cases virtually invisible. When, in addition, the radiation energies are low enough for not being detectable on the equipment outer surface, its existence has for most people in the industry been a secret. The report discusses transportation and deposition mechanisms, detection methods and provides some examples of measured results from the North Sea on equipment sent for maintenance. It is concluded that a regular measurement program for this type of contamination should be mandatory under all dismantling processes of transportation and fluid handling equipment for fluids and gases offshore and onshore

Radionuclide decay data-evaluation and dissemination

International Nuclear Information System (INIS)

Helmer, R.G.

1994-01-01

There are many applications of nuclear chemistry and physics, as the variety of contents of this symposium demonstrate. Many of these applications require a knowledge of data on the decay of radionuclides, e.g., half-lives and radiation energies and emission probabilities. For over 50 years, people have been compiling and evaluating the measured data to obtain recommended values of these quantities. This has resulted in numerous sets of recommended values, many of which still have scientific, historical, or national reasons for existing. This history provides a background to the current situation which involves the coexistence of the Table of Radioactive isotopes, the ENSDF file and the Nuclear Data Sheets, the Table de Radionucleides, IAEA Coordinated Research Program results, the ENDF/B-VI decay data file, etc. Visions of the future include new styles of evaluations and feedback from interested users

Modeling of radionuclide migration and a temperature dynamics in underground disposal of liquid radioactive waste

International Nuclear Information System (INIS)

Larin, V.K.; Zubkov, A.A.; Balakhonov, V.G.; Sukhorukov, V.A.; Zhiganov, A.N.; Noskov, M.D.; Istomin, A.D.; Kesler, A.G.

2002-01-01

Mathematical model of radionuclide migration and temperature field dynamics during underground disposal of liquid radioactive wastes is presented. The model involves the description of filtration, convective-dispersion mass transfer, sorption and desorption of radionuclides, radioactive decay, convective heat transport and hear transfer. Software making possible to conduct prognosis calculations of changing state of stratum-collector of radioactive wastes was made. Results of the simulation of temperature field dynamics and behaviour of radionuclides on underground disposal of liquid radioactive wastes of the Siberian chemical plant are performed [ru

DOS cones along atomic chains

International Nuclear Information System (INIS)

Kwapiński, Tomasz

2017-01-01

The electron transport properties of a linear atomic chain are studied theoretically within the tight-binding Hamiltonian and the Green’s function method. Variations of the local density of states (DOS) along the chain are investigated. They are crucial in scanning tunnelling experiments and give important insight into the electron transport mechanism and charge distribution inside chains. It is found that depending on the chain parity the local DOS at the Fermi level can form cone-like structures (DOS cones) along the chain. The general condition for the local DOS oscillations is obtained and the linear behaviour of the local density function is confirmed analytically. DOS cones are characterized by a linear decay towards the chain which is in contrast to the propagation properties of charge density waves, end states and Friedel oscillations in one-dimensional systems. We find that DOS cones can appear due to non-resonant electron transport, the spin–orbit scattering or for chains fabricated on a substrate with localized electrons. It is also shown that for imperfect chains (e.g. with a reduced coupling strength between two neighboring sites) a diamond-like structure of the local DOS along the chain appears. (paper)

DOS cones along atomic chains

Science.gov (United States)

Kwapiński, Tomasz

2017-03-01

The electron transport properties of a linear atomic chain are studied theoretically within the tight-binding Hamiltonian and the Green’s function method. Variations of the local density of states (DOS) along the chain are investigated. They are crucial in scanning tunnelling experiments and give important insight into the electron transport mechanism and charge distribution inside chains. It is found that depending on the chain parity the local DOS at the Fermi level can form cone-like structures (DOS cones) along the chain. The general condition for the local DOS oscillations is obtained and the linear behaviour of the local density function is confirmed analytically. DOS cones are characterized by a linear decay towards the chain which is in contrast to the propagation properties of charge density waves, end states and Friedel oscillations in one-dimensional systems. We find that DOS cones can appear due to non-resonant electron transport, the spin-orbit scattering or for chains fabricated on a substrate with localized electrons. It is also shown that for imperfect chains (e.g. with a reduced coupling strength between two neighboring sites) a diamond-like structure of the local DOS along the chain appears.

The management of hospital radioactive wastes

International Nuclear Information System (INIS)

Peyrin, J.O.

1992-01-01

Enquiries performed by nuclear medicine services together with ANDRA in order to characterize the radioactive wastes from hospital origin have led to suggest some improvements in the management of these products: improved screening on the production site by rationalized collection, planning of a local storage installation for decay of 125 I-containing products, systematic education of concerned hospital staff, in particular to prevent infectious risks, obtaining legislatively a change of class for tritiated and carbonated hospital radioactive wastes, which will be then considered as common wastes. The practical application of these arrangements in hospital by the 'radiation protection competent person' would liberate hospital departments from systematic appeal to ANDRA and thus result in money saving

Determination of natural radioactivity in beach sediments collected from Kovalam, Chennai

International Nuclear Information System (INIS)

Rajalakshmi, A.; Jananee, B.; Thangam, V.; Chandrasekaran, A.

2018-01-01

Long lived radioactive elements such as uranium, thorium, potassium and their decay products such as radium and radon are examples of naturally occurring radioactive materials abbreviated as NORM. All living things are exposed to ionizing radiation from NORM contributing to about 90% of human radiation exposure. The interaction of ionizing radiation with human body leads to several biological damages like leukemia, cancer etc due to damage and modification of cells and tissues in the body. Hence, the present work is carried out to determine the natural radioactivity of beach sediments along Kovalam Beach, Chennai. Associated parameters are also calculated

Evaluation of IAEA Clearance Concept for Low-level Radioactive Waste from a Radioisotope Research Institute.

Science.gov (United States)

Yumoto, Yasuhiro; Okada, Shigeru; Kinno, Ikuo; Nagamatsu, Tomohiro; Nouso, Kazuhiro; Nakayama, Eiichi

2016-05-01

The clearance of solid low-level radioactive laboratory waste (LLRW) after decay-in-storage (DIS) obtained from a research institute and thoroughly separated using the separation and classification protocols presented in this study was evaluated. The radioisotope (RI) content of incinerated LLRW from the specified RI research group (group A); the RI content of LLRW obtained in fiscal year 2000, which contained radionuclides with half-lives of less than 164 d (LLRW2); and the RI content of the LLRW reported in group A's disposal records were compared. The LLRW2 and LLRW of group A were incinerated after 2 y of decay-in-storage and immediately after storage, respectively. The highest ratio of the RI of incinerated LLRW to the value in the disposal records was 2.52 for ⁵¹Cr. The radioactivities of radionuclides in both the LLRW2 and LLRW for ³⁵S, ⁴⁵Ca, ⁵¹Cr, ¹²⁵I, ³²P, ³³P, and ⁹⁹mTc and the incinerated ash after 1 y later of decay-in-storage were below the clearance level defined by the RS-G-1.7 of the International Basic Safety Standard without contamination by ³H and ¹⁴C. These remains contained very small amounts of some long-half-life radionuclides of natural origin after 7 y of decay-in-storage. This LLRW separation protocol was effective for the separation of ³H and ¹⁴C. LLRW2 after 2 years of DIS and its incinerated ash after one year later of DIS were below the clearance level for radioactivity and radioactivity concentration.

Freedom: a transient fission-product release model for radioactive and stable species

International Nuclear Information System (INIS)

Macdonald, L.D.; Lewis, B.J.; Iglesias, F.C.

1989-05-01

A microstructure-dependent fission-gas release and swelling model (FREEDOM) has been developed for UO 2 fuel. The model describes the transient release behaviour for both the radioactive and stable fission-product species. The model can be applied over the full range of operating conditions, as well as for accident conditions that result in high fuel temperatures. The model accounts for lattice diffusion and grain-boundary sweeping of fusion products to the grain boundaries, where the fission gases accumulate in grain-face bubbles as a result of vacancy diffusion. Release of fission-gas to the free void of the fuel element occurs through the interlinkage of bubbles and cracks on the grain boundaries. This treatment also accounts for radioactive chain decay and neutron-induced transmutation effects. These phenomena are described by mass balance equations which are numerically solved using a moving-boundary, finite-element method with mesh refinement. The effects of grain-face bubbles on fuel swelling and fuel thermal conductivity are included in the ELESIM fuel performance code. FREEDOM has an accuracy of better than 1% when assessed against an analytic solution for diffusional release. The code is being evaluated against a fuel performance database for stable gas release, and against sweep-gas and in-cell fission-product release experiments at Chalk River for active species

Estimation of radioactivity in tobacco

International Nuclear Information System (INIS)

Nain, Mahabir; Gupta, Monika; Chauhan, R.P.; Chakarvarti, S.K.; Kant, K.; Sonkawade, R.G.

2010-01-01

The link between cigarette smoke and cancer has long been established. Smokers are ten times at greater risk of developing lung cancer than that of non-smokers. Tobacco fields and plants also have higher concentration of uranium and consequently large contents of 210 Po and 210 Pb belonging to uranium and radium decay series. These radio-nuclides have long association with tobacco plants. 210 Pb and 210 Po, decay products of the uranium series get dissolved in water and are first transported into plants and subsequently to the human being. Also, the uptake of radionuclides into roots from the soils and phosphate fertilizers along with direct deposition of 210 Pb by rainfall represents the principal mechanism of incorporation of 210 Pb and 210 Po into the tobacco plants. Uranium present in soil enters the plants through roots and gets distributed in various parts of the tobacco plants. This phenomenon may cause high intake of uranium and its radioactive decay products leading to harmful effects in human being. In the present work, Gamma spectrometry (HPGe detector of high-resolution gamma spectrometry system) has been used at Inter University Accelerator Center (IUAC), New Delhi, for the measurement of activity concentrations of 238 U, 232 Th and 40 K in some tobacco samples. The alpha radioactivity of the leaves of the tobacco plants was measured using plastic track detectors LR-115 Type-Il manufactured by Kodak. Measurement of track densities (track cm -2 day -1 ) shows variation on the upper face and the bottom face of the leaves for the plants. The track density due to alpha particles is higher at bottom face as compared to top face of the leaves. (author)

Laser assisted nuclear decay spectroscopy: A new method for studying neutron-deficient francium

CERN Document Server

Lynch, Kara Marie

2015-01-01

Radioactive decay studies of rare isotopes produced at radioactive ion beam facilities have often been hindered by the presence of isobaric and isomeric contamination. The Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN uses laser radiation to stepwise excite and ionize an atomic beam in a particular isomeric state. Deflection of this selectively ionized beam of exotic nuclei, from the remaining neutral contaminants, allows ultra-sensitive detection of rare isotopes and nuclear structure measurements in background-free conditions.\

Effective use of product quality information in food supply chain logistics

NARCIS (Netherlands)

Rijpkema, W.A.

2014-01-01

Food supply chains have inherent characteristics, such as variability in product quality and quality decay, which put specific demands on logistics decision making. Furthermore, food supply chain organization and control has changed significantly in the past decades by factors such as scale

ZZ NUCDECAYCALC, Nuclear Decay Data for Radiation Dosimetry Calculation for ICRP

International Nuclear Information System (INIS)

2002-01-01

1 - Description or function: The Dosimetry Research Group (DRG) of the Health Sciences Research Division at ORNL has for several years maintained data bases of nuclear decay data for use in dosimetric calculations. The data on mean and unique energy plus intensity have been previously published, in abridged form, in Publication 38 of the International Commission on Radiological Protection (ICRP 1983). This data base was designed to address the needs in medical, environmental, and occupational radiation protection. DLC-172/NUCDECAY is required by the CCC-620/SEECAL program to calculate age-dependent specific effective energies. 2 - Methods: The unabridged data used in preparing ICRP Publication 38 are distributed in electronic form in this package. The collection consists of data on the energies and intensities of radiations emitted by the 825 radionuclides reported, although abridged, in ICRP Publication 38 plus an additional 13 radionuclides evaluated during preparation of a monograph for the Medical Internal Radiation Dose (MIRD) Committee of the Society of Nuclear Medicine. Each collection is contained in an ASCII file (INDEXR.DAT) which is a sorted list of the radionuclides containing the decay chain information. The utility code DecayCalc extracts the decay data from the library for radionuclide(s) specified by the user. It computes the activities of radionuclides present after decay and ingrowth over a user-specified time period from 1 minute to 50 years. Decay data for any decay chain may be displayed and printed either in tabular form or graphically. DecayCalc, in a slightly modified version, will be a part of CCC-553/Rascal v3. DecayCalc is a Windows application that runs under Microsoft Windows 95 or 98, or Microsoft Windows NT 4.0 or later. The Compac Fortran 77 compiler was used to compile the code. The full source for DecayCalc is not provided but will be distributed when Rascal V3 is released

Abnormal radioactive decays out of long-lived super- and hyper-deformed isomeric states

International Nuclear Information System (INIS)

Marinov, A.; Gelberg, S.; Kolb, D.

2000-01-01

Complete text of publication follows. Recently (1-3) long-lived isomeric states have been found in the super- and hyper-deformed wells of the potential. These isomers manifested themselves by abnormal particle decays. An isomeric state in the superdeformed well of the potential in the parent nucleus can decay by very enhanced α-particle groups to superdeformed states in the daughter (1) or by very retarded α-particles (3) and also by protons (2) to normal states in the daughters. Similarly an isomeric state in the hyper-deformed well may decay by very retarded α-particle groups to superdeformed states (3), or by very enhanced α-groups to hyper-deformed states in the daughter nucleus (4). All these very unusual decay modes have been observed experimentally (1-4). For instance, a very high energy α-group of 8.6 MeV with 40d ≤ t 1/2 ≤ 2y (retardation factor of ∼10 13 ) has been observed in 195 Hg and interpreted as a III min → II min α-transition (3). Likewise, relatively low-energy and very enhanced α-particle groups (enhancement factors of 10 5 to 10 7 ) have been seen in several actinide sources and interpreted as due to II min → II min and III min → III min transitions (4). These unusual decay modes introduce new considerations in the study of heavy and superheavy elements. For instance, if low-energy α-particle groups around 4.4 - 4.6 MeV have been seen in nature (5), they may be interpreted as due to very enhanced III min → III min transitions in the superheavy element region around Z = 108 (eka-Os) with t 1/2 ∼10 8 y rather than ∼10 15 y as expected for normal α-transitions of such energies in this region, or due to very retarded III min → II min or II min → I min decays in nuclei around Os itself. In both cases, if such activities have been seen in nature, they indicate that the existence of the II min and III min isomeric states may be important in the nucleosynthesis process. It should be mentioned that long-lived high

β decay half-live measurement of 22 very neutron-rich isotopes in the Ti-Ni region

International Nuclear Information System (INIS)

Czajkowski, S.; Ameil, F.; Armbruster, P.; Donzaud, C.; Geissel, H.; Kozhuharov, C.; Schwab, W.; Bernas, M.; Dessagne, P.; Miehe, C.; Grewe, A.; Hanelt, E.; Heinz, A.; Jong, M. de; Steinhaeuser, S.; Janas, Z.

1997-01-01

Very neutron-rich Ti to Ni isotopes were produced in fragmentation of a 500 MeV/u 86 Kr primary beam on a Be target, separated using the Fragment Separator at GSI, and implanted in a set of PIN-diodes where β-decay particles were detected. From time-correlations analysis the unknown β-decay half-life of 22 isotopes were determined. Their values are within 10 -1 s. The β decay spectrum of 70 Co is presented as resulting from an analysis of the first β particle detected after ion implantation in the same detector. Also are presented the example of 3 β decay chains for 65 Mn and 66 Mn. The identification of such chains was instrumental in reducing the influence of background noise in the time correlation analysis while it allows life-time determinations of high confidence

Radon adsorbed in activated charcoal—a simple and safe radiation source for teaching practical radioactivity in schools and colleges

Science.gov (United States)

Al-Azmi, Darwish; Mustapha, Amidu O.; Karunakara, N.

2012-07-01

Simple procedures for teaching practical radioactivity are presented in a way that attracts students' attention and does not make them apprehensive about their safety. The radiation source is derived from the natural environment. It is based on the radioactivity of radon, a ubiquitous inert gas, and the adsorptive property of activated charcoal. Radon gas from ambient air in the laboratory was adsorbed into about 70 g of activated charcoal inside metallic canisters. Gamma radiation was subsequently emitted from the canisters, following the radioactive decay of radon and its progenies. The intensities of the emitted gamma-rays were measured at suitable intervals using a NaI gamma-ray detector. The counts obtained were analysed and used to demonstrate the radioactive decay law and determine the half-life of radon. In addition to learning the basic properties of radioactivity the students also get practical experience about the existence of natural sources of radiation in the environment.

Radon adsorbed in activated charcoal- a simple and safe radiation source for teaching practical radioactivity in schools and colleges

International Nuclear Information System (INIS)

Al-Azmi, D.S.

2014-01-01

Simple procedures for teaching practical radioactivity are presented in a way that attracts students' attention and does not make them apprehensive about their safety. The radiation source is derived from the natural environment. It is based on the radioactivity of radon, an ubiquitous inert gas, and the adsorptive property of activated charcoal. Radon gas from ambient air in the laboratory was adsorbed into about 70 gram of activated charcoal inside metallic canisters. Gamma radiation was subsequently emitted from the canisters, following the radioactive decay of radon and its progenies. The intensities of the emitted gamma-rays were measured at suitable intervals using a NaI gamma-ray detector. The counts obtained were analysed and used to demonstrate the radioactive decay law and determine the half-life of radon. In addition to learning the basic properties of radioactivity, the students also get practical experience about the existence of natural sources of radiation in the environment. (author)